Just wanted to let you know you're NOT alone at all. Almost EVERYTHING you said I feel too. I don't drink either, and it's a personal choice that I feel quite comfortable with but I have little verging on NO experience with clubbing, drinking and most things that others do my age, which DOESN'T say I'm a nun and don't enjoy myself, I just choose to do it a different way.
I go out and dance and have fun, go to cinemas, shopping etc. I just choose things that are more for me and I know myself too well and know that I'll never change my beliefs for anyone but I do understand Uni will change me a lot.
When you say you feel detatched from others our age, I empahise. Totally.
I suppose we've just got to be ourselves and do what feels right to us. Dancing isn't so much an issue for me as I've studied dancing etc but pubs/clubs do have areas where you don't need to dance and if you don't want to....DON'T.
That's what I've come to realise lately. People worry about "what if" in these situations ... if you don't want to, YOU DON'T HAVE TO and I think people forget that a lot.
Be yourself, do whats comfortable for you and BELIEVE me, there'll be lots of others like you (I'm 18 and starting Uni in a matter of days too!) and you'll be fine!
xx