girl I love moving to a different university around 4hours by train

You're quite right to not want to put as much effort into another girl. Because relationships at their best are pretty effortless. Or at least any effort you put into it is counterbalanced by the effort she puts into it. With 2 people as a partnership being more efficient than 2 single people.
In terms of effort of you doing stuff to impress the other person: that's a mug's game. The inner you should be an attractive person, just because of the way you are for you, for your own everyday habits and ongoing goals and purpose in life. So that all you need to do is to allow women to get to know you, without you making any special effort, and a proportion of them will fall in love with you.
You're quite right to take future relationships less seriously. Because love grows and thrives in lightness.
No you shouldn't tell her how you feel and you shouldn't ask her to be your girlfriend. That's too likely to reduce her attraction to you.
You should sort out the logistics for you to make love with each other and then take the lead in paving the way for this to happen, whilst doing it in a totally non-rapey way, with you being absolutely fine if she doesn't follow your lead. Shared physically intimate experiences cement the love between 2 people.
Maintain the frame that each of you are and will be free agents, with you being fine if she sleeps with other men in Manchester, because even though it will hurt you a bit, you want her to grow and develop as a person and have her freedom.

We were going to the same university originally but she changed last minute, and we went on a date the other day and I didn’t kiss her but there was a little intimacy, im thinking of taking her out again next week before I leave to uni.
Maintain what frame? I wouldn’t be okay with her sleeping around with other men no

Maintain the frame that every time you and her meet in the next few weeks is an opportunity for you and her to enjoy life as much as it's possible to enjoy life. That life doesn't get any better than the two of you going on mini-adventures together. So that when you're with her, your frame is that you're primarily focused on the here and now. And in enjoying each moment with her.
If you don't have sex with her in the next 2 weeks, you'll probably never have sex with her.
If you don't have sex with her, that's fine. Your life will go on and other women will come into it.
If you do have sex with her it should be an amazing adventure for you and her.
You will be more attractive to her if you maintain the frame that when she's at Manchester, she's 100% free to sleep with whomever she wants. With there being the (unspoken unless she brings up the subject) frame that you'll be a free agent too.
Of course there will be a selfish corner of your heart that will want her all to yourself. But the logical and noble part of your brain should over-rule this Gollum "My Precious!" side of you. That amount of self control is attractive to women.
If she goes off to Manchester without having had sex with you, it would be quite evil for you to want her to remain celibate. Better to be a good guy and to want the best for her, from her point of view.

We can only meet once or twice more before she leaves for university… she leaves next week.
So how can I even have sex with her let alone kiss her.. where would we even do it.
You don’t think I should visit her in Manchester like once a month and make it official with her?
I’m enjoying the moments with her, yes. Also I doubt she’ll have even have sex with anyone. She’s not the type to cheat either.

I’m not sure what to do, we’ve been talking for like 6 months nearly everyday, but I’ve known her for 2 YEARS in college. I’ve got to know her more than she realises, she’s very different to all the girls that have liked me in the past.
She’s going Manchester I’m going Southampton.
Over the 6 months we’ve been on dates, but i haven’t asked her to be my gf because of her late replies and mixed signals.
all in all, I love her, like I would take a bullet for this girl and she doesn’t even realise. She makes me so happy l, I love spend time with her and she’s able to make me laugh and I can’t imagine her not in my life? So it’s going to end in heartbreak if I don’t marry her
And for all those who say “you’ll meet someone new in college” I don’t want to put the same effort into another girl again and I will probably not take any relationship as seriously in the future.
College starts in 2 weeks, do i tell her how I feel about her and that I’ve fallen in love and ASK start a relationship with her, despite we’re about to go to a different city for 3 years.
P.S -> we are in the same city for 5 months across the year (breaks) but 7 months of the year we are in uni.
I could visit her at least once a month I have family in the city she is in too or Should I just give up (some people say it won’t work out)

If you look at DK's posting history, everyone gets the same advice about 45 minute first dates, attraction, mini adventures and sex, so don't take it seriously.
I dated a guy for 3 months, we had enough time together to decide to make it official and, both having been in the military, we've navigated the whole long-distance thing, which was often more than 2 hours each by train.
If you are that interested in this girl, you would have sorted things out with her to be in a relationship. You've let it drift, so does she really mean that much to you? You've still got time to salvage it, so if you are serious meet somewhere to have an actual meaningful conversation and see if you are both of a mindset to make it work. And as above, don't get into the whole marriage thing; if you can't discuss 'mixed signals' there is no way you'd cope with the responsibilities and decisions that come with that kind of commitment.

Maintain the frame that every time you and her meet in the next few weeks is an opportunity for you and her to enjoy life as much as it's possible to enjoy life. That life doesn't get any better than the two of you going on mini-adventures together. So that when you're with her, your frame is that you're primarily focused on the here and now. And in enjoying each moment with her.
If you don't have sex with her in the next 2 weeks, you'll probably never have sex with her.
If you don't have sex with her, that's fine. Your life will go on and other women will come into it.
If you do have sex with her it should be an amazing adventure for you and her.
You will be more attractive to her if you maintain the frame that when she's at Manchester, she's 100% free to sleep with whomever she wants. With there being the (unspoken unless she brings up the subject) frame that you'll be a free agent too.
Of course there will be a selfish corner of your heart that will want her all to yourself. But the logical and noble part of your brain should over-rule this Gollum "My Precious!" side of you. That amount of self control is attractive to women.
If she goes off to Manchester without having had sex with you, it would be quite evil for you to want her to remain celibate. Better to be a good guy and to want the best for her, from her point of view.

She is in two minds about long distance and she’s too shy to say aswell but we’ve been dating so we’re not really ‘friends’
You don’t think I should tell her how I feel? Not even over text? And instead you want me to ask about whether she wants to be in a long distance relationship? Ive been treating the past 6 months with her like a long distance relationship as I was in different countries and we went on dates when i came back and talked lots. Im willlimg to put all the cards on the table and tell her she’s my first love? That way I know I tried my best, and I wont regret it in the future

I did something similar to this, we spent 2.5 years long distance, started living together during our postgrad year (when I moved uni) and are now both 25 and engaged. It can work out. However, you need to ask her a couple of questions before you know where you stand. Do that, and less of the poetry.

Dating isn't a long-distance relationship; it's just dating. Unless you discuss things seriously - which clearly you haven't - there's no commitment, no priority, no exclusivity.
Tell her you want to be in a relationship with her. You want to give long distance a try. You'll discuss each other's timetables and workload and arrange to call/facetime regularly and meet up, possibly monthly. If she saysno, you know where you stand and can start to move on from it. Though it begs the question how interested she is if she won't properly consider an LDR, which is perfectly doable if you nothing put the effort in.
You snooze, you lose...

What questions do you reccomend asking especially for a LDR to work out?

I really enjoy spending time with you, I want things to become closer between us, how do you feel about that?

That’s broad though? should I not imply more

So should I ask her over text or arrange to meet her one last time? Id hate to tell her and she be put on the spot