i remember being really scared about starting college, too...

i don't know the demographics for your particular college, but often there are a whole heap of people who moved there, and they are all similarly scared about whether they will make friends. so... you should find a whole bunch of people who are being friendly, and trying to make friends with other people :-) one thing that i really loved about college is how different it was from school. hanging out by yourself, eating your lunch by yourself, hanging out in the library is completely fine. even the people who do have lots of friends probably won't find they have friends in every class they take, so there tends to be lots of opportunities to meet people. and study groups... you will tend to meet people in your classes. exams / assignments etc put stress on people and stress is a good social facilitator.

joining a club can be a good way to go. join something that interests you and you will have a nice chance to meet some people who share the same interest. being gay is a lot more accepted at college than it is at school, too. whether you share about your sexuality or not is completely up to you. i wouldn't be surprised if you didn't manage to find some friends who are more openly gay.

there will be other people around your age there, as well. especially in math / comp sci if you are into that... it isn't that uncommon for people to be 17 when starting... and i think you will find the age thing ok, really :-)