@hatiek,
Don't do it. You are right that it would get awkward. Your job is worth more than this.
By the way - a pro tip - the
first time you compliment someone, for God's sake, don't call them
sexy. Call them pretty or charming or cute or handsome (if appropriate) or funny but don't use the word
sexy. It is like skipping over a few dozen steps of the process. Of course not everyone behaves or thinks the same way, but you were served a softball and you crushed it with a bulldozer instead of lightly batting it back.
Don't go that fast. Seriously. You've got nowhere to go from there, and it's too unambiguous, particularly with someone you work with. You essentially told her you'd like to **** her. Even if that's true, you had no idea whether she would be receptive to any advances at all.
Christ, if someone at an office told me I looked sexy, I would be contacting HR and complaining of harassment.