Frodo was around 50 during the events of lord of the rings, making him an adult comparable to maybe a 30yo human. Sam was a bit younger and Merry & Pippin were basically teenagers

Boromir was a great man himself too. Just because the ring was able to fuck with his mind more than it did with Faramir’s, doesn’t make him any lesser in anything but this specific thing, which ended up with his fall