Good for you, giving it a go even though you're nervous! That's what life's about! Hey, what's the worst that can happen? They say no, give you some feedback, and maybe you can improve and try again. That doesn't really suck, at least you tried. The best that can happen is that you get in, and head off to follow your dreams.
Don't worry about getting stuck. Just because you draw/paint/whatever, doesn't mean you can't still do stuff in the theatre, and vice versa. You only get stuck when you allow yourself to get stuck. If something doesn't work, try something else. When I started uni, I was originally studying HR. Then I decided I didn't like it and changed to Marketing. I didn't like that either, so went back to HR and now I work in HR and I love it to death. It didn't hurt me, it actually was really great for me and it still contributed towards my final diploma. Maybe in your first year you would be able to try out both, then fully commit to one for the rest of your study and keep the other a hobby. I'd recommend speaking to a careers counsellor at one of these wonderful colleges, or at least an administrator who understands how the courses work.
I'm a little confused about wether your choice is A) to pursue your creative instincts OR stay at home and be safe, or B) pursue arts/design OR theatre/performance, but I hope what I said helps you. If it is A, then I do have one thing to add - as a creative person myself (albeit not particularly talented, I just like doing it) if you do take the second option, at least make sure you still have some sort of outlet, otherwise you'll likely explode. Take the safe road by all means, but paint on the weekends
Good luck with your applications