I worked long before I could legally enter contracts. Only one of my jobs has had an employment contract.
I agree with your point that many reach maturity before 25 or even 18, however I don’t think enabling those fortunate few is worth stripping the protections of minority from the rest.
I don’t follow your argument about sex ed and consent.
Sex ed should start as soon as kids can talk, to keep it from being stigmatized and to prevent predation. There is no need to wait until a child reaches sexual maturity for that; in fact, at that point it is too late.
As to driving, most people shouldn’t be driving, period. We are, in general, not good at it. Leave it to the professionals.