The main issue with any age of consent lower than like late teens is that A) parents don't regulate their children's marital lives anymore, so comparing modern age of consent to medieval age of consent is fucking dumb, and B) this makes hypergamy like 10x worse. Imagine having to compete with 24 year olds for girls when you're 15.
But if we go by "maturity", I would quite confidently say that it should be illegal to have sex with minorities as they are literally as intelligent as 12 year old whites