I learned about weapons while doing my compulsory service in the army (20 years ago, not so far...) and the first weapons I've ever fired were a Garand, an MG42/59 and a Beretta 9mm. No .22....
Joining the army to get access to free ammo seems a bit extreme. If that's not an option, then a 22 is the way to go. Learn how to shoot with low cost ammo and no recoil to deal with. Then go to centerfire.
What I was pointing is that even young one can start (if finds a good instructor) with larger calibers.
Life is too short to fire boring ammo (I'd rather shoot 50 good 9mm per session than a couple hundred .22, but it's my personal taste and, as we say de gustibus non desputandum est