Newcastle also has the reputation of being one of the best student cities, not just party cities. By that I mean, going out clubbing or partying or whatever is only one of the many things you can do there.
I went up to Newcastle for a weekend a couple of months ago and it's such a nice city, very friendly, clean, with so many different things to do and see.
You certainly won't be the only person who doesn't want to party 24/7, there are loads of other activities going on during Freshers and throughout the year like pub quizzes, bowling, paint balling etc... And there are loads of societies to join to meet people that share the same interests as you.
Basically, don't worry; almost everyone will be feeling anxious about going to uni but you'll do great at Newcastle, it's a great uni and city!