Wouldn't the risk for brain damage be higher if you start at 7? I mean, that's seven more years of punches to the head. Please be concistent in your bad advising.
At 7 you have the advantage in becoming skillfull defence wizard. You'll be better than 99% of opponets and with right management you can avoid that 1% who has the killer instinct to go for the KO. Damn man at 7 year of age your motoric skills are developing and if you let them develop at boxing youll become untouchable in the ring! Now if you start at 14 your motoric skills are suffered and you have much higher chance to get KTFO'd than if you started at age of 7 when you had the chance to become motoric defence wizard.
If you start at 7 you box against other 7 year old, and no; you won't be better then 99%. What you will have is 7 more years of punches to the head compared to a 14 year old beginner.
I trained at a gym where almost everyone started as a teenager/adult. One of the MMA fighters for instance started at 27. An amateur champ on the USA Boxing team started at 18/19 (he's in his early 20s now). A bigger name UFC fighter turned pro at 26. Very little amateur experience before than, just a couple of pro boxing fights. All it takes is hard work and dedication. Talent is absolutely meaningless.
Bryant Jennings started boxing at 25 sergio Martinez started 21 Lucas Browne 31 Rocky Maricano 20's A huge part of Boxing is mental. If you want to box box. Age is a number, it's really deciding if boxing is what you want to do.