A little unsolicited thinking out loud here... it's hard to not project as a father. Whether or not it's a good idea to teach your own kid to fly probably comes down to your teacher/student relationship with your daughter.
My kids are only 5 and 7 but at times the instructional receptiveness and the ease with which they lose patience and basically tell me to get lost makes it seem like a good idea to delegate certain vocational lessons. I've watched them behave like angels and remain focused on a teacher when I know with me they'd be trying to climb onto my head. Daddy is just a different world.
I assume that at 15, your kid wanting to solo means she's flown with you a lot and has a history of good hands-on practical experience. I think I would still delegate to a more formal instructional relationship with a CFi who will objectively evaluate her readiness with both aircraft handling and aeronautical knowledge.
Some of the stuff that seems contrived I view as kind of a conceptual gatekeeper. We talking regs or physics? I can see the former not being as important but the latter is important to comprehend fully.
Been thinking about starting my commercial and instrument next summer and I've been looking for a study program too with a good iPad support. Everyone says Sheppard Air is the best for knowledge exam study, but I'm not sure it's as good for true teaching.
I'd check out this Jepp part 61 program, all electronic:
https://shop.jeppesen.com/All-Products/ ... 3367-63335On the other hand I do think it's nice to have real, tangible, paper books for studying. Especially since it's so easy to get distracted by notifications on a mobile device.