[Divine Soldier]

Children being as strong as adults who are equally magically potent is poor IC, so I fully support the -10% per year until they hit 18. It marks it as a clear growth period, and makes the child period a period of vulnerability - which is something that should be intrinsic with being a child.

As for age debuffs, my personal recommendation would be -1% dr per year beginning at 31 years old. It would make IC sense - the downside of age being felt slowly at first, and eventually building up to the point where it's significant.