I am a girl, and Ive had glasses for a long time and I actually prefer to wear them to class because contacts are just annoying in the morning. Ive never been told that I look like a nerd, and I feel that being called a nerd for wearing glasses is so outdated. Anyway, get some glasses that flatter your face. I personally go for dark rimmed glasses that tend to have larger frames rather than the small tiny little circular frames or whatever, and I try to find some that nobody else will really have the guts to wear. The pair that I have right now are by Bebe, theyre from my eye doctors, and they are half black and half hot pink. I get dozens of compliments on them. I also have this pair by Candies (again, from my eye doctors) that are black with purple sides--also get lots of compliments. Every year when i go to the eye doctors, I spend about 45 minutes trying on pair after pair of glasses, just so I can find the perfect ones that dont look dorky on me or make my head look big or whatever. Glasses can be tricky, but you just have to take the time to try on several pair-- even if you see a pair that you wouldnt normally like, try it on anyway because you never know what it will look like on you until you try them on!
I dont think glasses make eyes look smaller at all, if anything they make your eyes larger. If you find yourself feeling that your eyes look small, try wearing some eyeliner and mascara.