I'm far from being an expert but I WOULD NOT send that message if I were you. Here's why:
1. She told you that she can't make it, maybe another time. You shouldn't go from "another time" to assuming she doesn't want to see you again. It's way too reactive and makes you seem insecure. Maybe she really does have an audition to practice for or something more important came up. If this is the case you'll totally weird her out with that message. Why would you react like that? Why?
2. On the other hand, maybe she actually doesn't want to see you again. So what, fuck it. Plenty of girls out there. Your still coming off way too reactive and needy which is totally unattractive from the girls point of view. Do you think this message will make her change her mind and suddenly decide to take up your offer out? Realistically?
3. Think about how she will interpret your message. I think you took the neg a bit too far, "I would only break your heart." Are you directly trying to tell her you just want to fuck her and leave? (It's a great neg for other situations though!) Then, you totally contradict that by saying you'll be sad to lose her as a friend. wtf. How do you think she'll reply to that. I personally think she won't even text back.
I could be totally wrong and you might send that and get a perfect response from her, who knows? Just my opinion dude... good luck
