At age 12, with a ton of cousins and brothers and uncles, went hiking down the (shallower but longer) Bright Angel trail, spent the night at the bottom of the Canyon, then hiked back up the (steeper but shorter) Kaibob Trail.
WORTH THE TRIP!!!!!! WORTH EVERT STEP DOWN AND BACK UP!!!!!
I think what surprised me was how thin the "uncles" thought the air was at the top (8000-odd feet), compared to how much easier they were breathing 5000 feet lower at the bottom!
Sounds like a wonderful trip to share with your family.
OK, Ava is gone and I am off to the dungeon for my workout...I will just pretend I am hiking down the trail at the Grand Canyon. And I won't look down. LOL