Attraction runs on a clock.
She flirted for weeks. Touched your arm. Found reasons to be alone with you. And you were careful. Respectful. Waiting for the right moment.
The moment had a shelf life. It expired around month two, and by the time you asked her out, she'd quietly filed you under "little brother."
One of the hardest lessons inside the 22 Rules: women rarely wait. Interest either grows or it decays, and nothing decays it faster than a man who never moves.
Make the move while she's still inventing reasons to be near you.