I'm a mature student now but I once left my boyfriend/partner (we'd been living together for about 6 years) to take a job overseas (12hr flight away!). It was awful at the time and I cried for the first couple of hours of the flight because I was afraid that I'd never see him again. We spoke on the phone regularly and sent emails. After 3 months we spent a month together and got married, five months later he visited me for a 2 week holiday and four months after that he joined me.
Everyone said it wouldn't work. Nasty people told us that the other one was playing around (why do people do that?) but ten years later we are still married (and living together!).
I think over the long term it made the relationship stronger, we are both capable of independance but agree that we'd never want to do it again. As we had been together since I was young it gave me a chance of having a taste of the single life (living alone/shared accomodation, going out when I wanted, not having to think of anyone but myself etc) within the safety of a relationship. In the short term the relationship felt shaky, so many people told us that it couldn't work and going months without seeing each other was hard. We even got used to living without each other and it was quite an adjustment when we lived together again.
Don't give up your dreams of going to the university of your choice because of a partner. If the relationship is meant to be forever it will be and in the long term 4 years is a very short time and oneday will only be a vague memory that you are reminded of occasionally. If you go to university you'll still be in the same country and will have holidays together and hopefully some weekends. You'll be able to phone, text, email, chat, skype etc. If he can't wait then it obviously wasn't meant to be.