She's maybe looking for a relationship and you give her discredit when you've said: "enough for just 2", that's a bad answer, you should always be fun and assertive and you did not :\
You are showing to her your bad personality, the worst you can do is to get angry to her, chill out, girls do shit all the time!
I don't know what you should say, but when i screw the things up i don't text her and i act in person as if nothing ever happened.
My best tip is:
There is 2 realities in people minds, one is Live, other is online, texting, whatever...
When you have both and you screw one reality you can go along with the other, well... since you haven't connected both as one (which i believe you did because you invited her by sms to a live date, so you've connected both realities, so well fuck!).
But maybe she didn't notice that, who cares, try again, but don't text her! Talk to her in school as if nothing happened, see her reactions and fix the shit you did. But don't text her in a few days when you are fixing the shit you did! If you sms her, it will trigger her idea that you were an asshole to her and she'll avoid to text you back once again!
In school act if nothing happened, talk as you talked to her, don't talk about the sms you've sent to each other or what ever, and don't show that you are angry because she didn't reply to them! And the problem will disappear by itself.
One girl did this to me once, and i've learned the power that this has, it might seams stupid and i would think the same if i haven't tried it and had this personal experience.
Give it a try, you wouldn't loss anything!!!
Also make her friends a good friends of you, they would help you out when you need. Give them what they want, like help them on school and shit... They'll love you and want to help you guys out! Friends things
