What would you do in my situation with my prom date?

[Michael]

So I asked this girl to prom last week, I put roses on her car and wrote her a letter and in the letter I told her that we were going on a date soon. And i rushed to do it when I did because I heard she was suppose to hang out with this guy from some of my friends. So I asked her before they started hanging out. Well they hung out and she put on twitter "The start of something new" and "Tonight was perfect" that night. Well its been a few days now and today she had a cheer competition and she put on twitter "should I clean myself up before seeing him" . Well I've been thinking about it and I'm going to find me a different prom date. Because I'm no ones second option, because obviously putting flowers on her car and saying we're going on a date soon didn't mean anything special. And I'm pretty pissed. So what is your opinion?
Might I add I've known this girl for awhile and its not like this was out of no where.

[lola]

Good for you! Gosh darn it I wish more people like you had it all figured out. You have confidence, that is so attractive and you know where you are going. Plus you at least tried yet know your limitations. Bravo sir!

[Flower Power]

Dump her and find a new prom date...if you went through all that gesture and she is publicly saying she is going out with some other guy don't waste your time on her. Find someone who will actually appreciate what you do for her.

[MM]

I think moving on is a good idea. Though you might want to ask the next girl in person instead of telling her in a note.

[de Chicago]

Talk to her first. If you asked her to the prom and she accepted, you can't just ditch her because she may be seeing someone else. If you no longer want to take her (and that's fine) let her know now and tell her why too.

[Josie]

Well, I would stay true to myself. You should not be someone's "second best". I think you should go up to her and tell her to go with that one guy she supposedly "likes". I would break off the date. I would go with someone that actually would be really excited to go with me and cares about me versus someone that doesn't really care that they are using my time.