I Have a daughter that gets straight As without even trying, but she is only a soph. That ACT score is going to be dang hard to get. I guess the fact that she can do so well in HS without much effort might bode well for her chances at a higher ACT, but WOW, that is getting pretty dang high.
The crazy thing is that there are some dang smart kids with 3.8 GPA and 28 on ACT that aren't getting in to BYU. They end up going to BYUI which is fine, but they are there with people that pretty much get in just from graduating from HS, so it isn't much of a "reward" as far as that goes. If you get a 3.3 GPA, fine, you probably would have a real hard time handling BYU and shouldn't get in, but kids with 3.8 and are so close, it is kind of a bummer for them.