Grew up in a world where girls were only expected to be more mature than boys.

Nah. Girls tend* (and this is doing the heavyweight championship of this sentence) to be naturally more empathetic from my PoV, which coupled with actually faster develepoment and higher expectation of maturity produces the “mature and empathetic” image of girls. Also noticed back then that girls were more social oriented than guys. Guys got together to do a thing, meanwhile girls were fine just sitting around and talking.

* Half or more girls I met growing up still escaped this in varying degree, but baseline tendency was still higher than in boys where this was exceptional.

Although, all in all, it’s all based on personal experience so I may be way off the mark.