It's true that she clearly likes this guy, so this is difficult, but if you can also see that he likes you, then it shouldn't be an issue. Furthermore, it's not uncommon for girls to sense when other girls are in love, so it's possible that he was unaware that she was making progress toward him. Also, he will definitely let her know if she crosses boundaries and he doesn't like it. However, if you are certain that he likes you, then there shouldn't be any issues. When you finally muster the guts to confess, please let us know if he says yes!