I took two AP courses and three exams. The classes were worthwhile because they're good for the GPA boost. The exams? Well, I'll go one by one to say that, while good, they weren't great.
AP US History. This was worth 6 history credits in American history. As a history major, this might have been useful. It turned out not to be because US History wasn't required for a history major and I ended up taking so many history classes I stopped receiving credit. However, a person who made different choices could have maximized their use of this credit.
The rest shows the problems:
AP Statistics. Worth 3 credits. However, it did not fulfill the one math class I had to take - forcing me to take another math class. In the end, this was essentially wasted credits because it got me nowhere towards completing my degree.
AP English Language. I think that was its name. I took the test with no class and passed it. I got three credits. However, it did not count as an English course, forcing me to take the Freshman English course anyway. This was also a waste.
I'm not saying it's a bad idea. There are certainly positives (another nice positive is having more credits gives your priority when signing up for classes). However, it doesn't translate exactly 1 for 1 when you still have degree requirements to fulfill. I also don't think anyone should graduate from College before they turn 21, but that's a digression right there.
However, congrats to your daughter. It sounds like she worked hard and it'll hopefully pay off.