Who cares about creepy? Keep doing it until she tells you to fuck off, or until you feel stupid yourself. Being interested isn't creepy, persistance isn't creepy.

However, if you can't take a hint, just saying 'I has homework so I can't', two times, without adding something like '...but I'm free on (day) if you wanna do something then...', probably means she isn't very interested.

Whatever made her give you her number then has probably gone obsolete now.