I like someone here, should I tell her or would that awkward?

If you're currently PMing with her I don't see why asking if there's any reason why you telling her you might be harboring a bit more than your average interest in her.

Be diplomatic and avoid reacting to whatever answer you get. Unless you're asked why. Any woman that doubts herself enough to ask why is only playing with you and you should never allow a woman to play with your god given good intents.