Is there a way to make my room look more "teenage-ish"?!?

Posters. Put posters up of all of your favorite bands, people, actors, or even phrases all over your room. IF your parents are afraid the tape will peel the paint, you can buy poster tape which peels absolutely no paint and is very inexpensive. You could also look into buying a fun comforter to match your red walls. Pbteen has some you would probably like as well as delia's which is very teen-ish.