I travelled a little bit during my gap year. I also worked during my gap year to fund this. I just travelled around the UK - would have been able to travel more if I had been a bit wiser managing how much money I spent on my girlfriend at the time, and if I had worked for a different company or doing something else: I knowingly and willingly became a care worker despite it attracting very little pay, which I actively decreased as time went on because I frequently called out the bosses for the poor treatment of our patients and staff... which only ever led to my hours being cut but at least I could sleep at night and look myself in the mirror.
Also, budgeting helps. You're young, you want to see stuff, do you really care about travelling fancy? Do it on the cheap. Cheap airlines like Ryanair, take trains, stay in hostels, etc etc etc...
Is it weird going to uni with people a year younger than you? Nope. Matter of fact, it is unnoticeable. Hell, I know two people that are 23 and in first year and you just wouldn't be able to tell unless they told you. Age is but an illusion in young adulthood, nobody notices nor cares.
Solo travelling is... alright. I'd much rather travel with friends but that boils down to personal preference. Also, the experience of travelling solo will change depending on where you go and how you do it - the experience I had of travelling in trains and buses and staying in hostels would be much more different than someone flying around the country and staying in nice hotels. I didn't make friends in my travels, but I wasn't seeking to - you'll probably never see them again and unless you happen to be travelling the same way for a bit, you also won't form a meaningful relationship. But that's alright in my opinion!
And yes, I would definitely recommend travelling. It's a beautiful world, see it
