Yes I've heard of Jenkins, some good dogs trained!

Mate I would suggest you start off with your own dogs to train, get some giveaways eg then build up a reputation/record. Owners are a bit chary about sending their dogs to a newcomer as they don't know for sure how the dog will be trained even if the father is on hand to help.
Being a young person, you might have a bit of trouble convincing owners to give you a go unless you can lay on board your training methods (how you train, feed etc)

Many owners have had bad experiences with young newcomer trainers that soon gave up the sport because they took to drinking, chasing women once the hormones kicked in lol

Get some experience under your belt with your own dogs, young fellow, and if you do well, pretty soon you won't have to ask for dogs to train, owners will be knocking at your door and you'll be the one turning them away ;-)