Well, it depends. I think you mean "Université" by "college". The mistake is often made I think. "college" is "Université".You're 17, so I guess it's University you're talking about, isn't it?
Then what you mean by "
I'm going to start college" is in French : "
Je vais entrer à l'Université" I guess if anyone could concur, it would be better, but I really think that "
entrer à l'Université" is okay.
I think we need to clear something up:
College in British English is not used as in American English.
Whereas in AE it means
university, in BE it is the two years
before university (sixth form, if part of a secondary school; college/sixth form college, if a separate establishment). L'équivalent en français serait les années du Bac. Je suis pas sure du système américain avant l'université.
Je pense que c'est pour ça qu'ici on voudrait plutôt dire
lycée. Tout cela dit, dans certaines grandes universités en Angleterre (les plus anciennes) - Oxford, Cambridge et London - il existe des '
colleges' qui font parties de l'université et qui ont une administration séparée et sont, dans un sens des universités elles même. MAIS les étudiants seront diplomés sous la '
University' et non pas sous le
'College'. Par exemple, quelqu'un qui fait partie de
'Keble College' à Oxford, va quand même recevoir un diplôme de Oxford.
However, in University of London, I think it's even more complicated because you'll get the Medical colleges that are completely separate and though a student will still receive a certificate authenticated by the College, they are still included in the University of London. I'm not sure on what levels. It may be due to quite a bit of devolution of administrative powers etc. to each of the colleges, I'm not actually sure. Perhaps someone else can shed some light on the history of it.
SO, generally college in BE should mean sixth form college but it's useful to verify because different people will have different habits of language, which aren't necessarily wrong, but need to be understood before assuming. These are the things that make learning languages difficult sometimes. Ihope this wasn't a useless contribution.