Necklaces, bracelets, nail polish, finer fabrics... I don't know anything about fashion, just naming stuff that I find pretty. Sorry for being vague, but I'd suggest you start looking for all sorts of different fashions across the board and see if something calls out to you. You're looking to express yourself after all.
Only one way to find out! And i'd say polish is a good way to gauge. Can blame it on someone else (oh my friend wanted to practice or something) and its easily removable if it does end up being a big deal for your parents