One question is whether your DD is able to work through all the problems in the text first? It takes a huge amount of time, especially if she's jumping into a new area of math, and she may be struggling to get through it all.
Our experience in AoPS Algebra I was that the challenge questions were pretty easy (with no more than 1-2 that required some thought) if - and only if - all the textbook work had been completed first. When we fell behind in the textbook work, e.g. doing the basics but not following through with the full set of harder questions at the end of the chapter, then DS was unprepared for the homework assignments.
In terms of how much help you offer, a compromise might be to offer stronger support working through textbook questions, and step back from the homework challenge questions?
