Yes. A 12 year old can do it and it's a great trip. It's a deep canyon and rocks roll down into the rather smallish river. That makes certain sections very technical. Other sections, you can get out in the little plastic kayaks (rubber duckies) and safely paddle behind the main rafts.
I would suggest mid to late July. It can be cold and rainy in early June. Mosquitoes in late June. By August you're going to have smoke. It could be just a haze, it could be thick. In any case, there will be smoke in August. I think mid-July is the sweet spot. (Although I went in mid-August 8 years ago and the smoke was negligible.)
I assume you will be going with an outfitter. I went with these guys and was very pleased. Pleased with their expertise, pleased with the meals, pleased with the general camaraderie.
https://www.idahoriveradventures.com/?g ... AfEALw_wcB