Supposedly I should've texted her right away?
AFAIK waiting (less or up to) a week can only make you seem more interesting. OTOH it can make you seem disinterested. OTOH you may seem too desperate when texting her right away. OTOH etc etc.
I just realised that all my social successes were lucky (In your situation, I did not text for a week because I was busy doing stuff, and the fact that I did that is what actually made her interested in me (6.5 yrs now and we're getting married in august), as the information that you provide (and any sane person could never acquire) is just too little to know what to do exactly when. So my only tip is: wing it, everyone else does, and nobody really knows what to do in situations like these.
But I am genuinely impressed by the fact you actually asked for her number. I've never been able to do that. You are awesome. Also, what Vector said.