Professional archer here; no 12 year old can pull a 50lb draw, especially any recurve or longbow format. Re. compound bows, maybe if they were abnormally strong they could get to the let off point just once where the cams drop the weight down to 8lbs, but I doubt it. They’d have to pull 50lbs many inches to get there. Most 12 year olds will start on 14-18lb bows and by the time they’re full adults age they’d be pulling 54lbs ish if they were really fit, had great technique and a decent enough amount of muscle. I shoot every day and pull 56lbs, by the end of sessions I’m absolutely shattered.

Apart from that nitpick, really good explanation of the muscle use.