I don't think you're overreacting. At 12 years old, 3 hours away, I'd expect contact each night. I'm amazed you're only texting and not calling, I think that's very strong of you lol. And really I don't see how she can be upset with a text, just send a quick reply and get back to whatever she's doing. Though I do notice she's happy to text when she needs something.

I'd call and set out some ground rules. She needs to call/text by x time each night, and if for some reason she can't she needs to let you know why first. She is probably loving the independence, but you still need to know she's ok and she can't expect this situation to be as if she's an adult moved out on her own.