Well, I'm going to be blunt and give you my observations.
You texted her because you `chickened out' (your words). So it probably was clear from the beginning that she `owned' you. So for that reason, she probably wasn't that into you. So I just cannot see her feeling compelled to take the initiative of going through her schedule, thinking about what she wants for lunch tomorrow, and then finding the time and energy to meet with you. So she probably won't return your text.
On the other hand, if you had gotten her on the phone and handled your end of the conversation well, or if you had left her a good phone message, she might have found herself really looking forward to lunch with you. You see, a lively voice with powerful tonality conveys so much more than a text message, and so there's a much better chance that she'd call back. She would have much more to go by, make sense?
If you don't hear back from her, you can try her again next week. If you don't see her in person, use the phone this time, won't you? And in the meanwhile, read the DJ guide.
EDIT: I read some of the other posts here. Guys have to realize--girls give out their number to a guy because when he asked, they realized that they wouldn't mind talking to him again if he's willing to put in the effort. I'm not sure how much giving out her number commits her to going out on a date with a guy. On the other hand, I do think that if a girl lets a guy buy her dinner, it really should mean that she is interested and available.
