Two of my daughters shot 9mm compacts from the age of 12.

One dropped out, but the other really enjoys it. Now that she has settled into the sport, I've bought her a 75B that we will put on her name.
She is now 14.

We have just done it for my son (16) and his FA is now on his name.

Get GOSA to assist, especially with the Comp application, as that is where the biggest hurdle is.
His Comp took 4 months to approve, the actual FA license took 5 weeks.