If you're a dude, never ever ever ever ever confess your feelings towards any woman. Keep that shit a secret, you should only wait for her to confess to you, and if she does, never say "Oh I liked you for a long time too".
You are shooting yourself in the foot, I know because I've done it and regretted it every time. Women do not like it when men confess their feelings, even if she did somewhat like you, doing so will make her not like you at all anymore.