Firstly, welcome to the forums mate.

Secondly things are nowhere near as bad as you think! For a start you got the girl's number and she seems really interested in you so you're already halfway there. I'd just text her something playful and fun (have a look under the list of text messages for some openers - there's some good ones in there, used to great effect), and take it from there.

Keep it real
Blanca