Too young to fly?

My son:
So, I soloed in gliders at 14.
30 hrs later and 15.5y, I want start private, instruments etc…
I know I can’t get the private before 17, but did any of you get more than minimum (i.e. instrument) training before 17, due to young age?

No, it does not make any sense to do instrument training before obtaining the private certificate.