Marvel HAS tried to address aging on occasion; for some characters, like Cap, it doesn't matter because you just make the "revived-on" date fuzzy, but for others there's had to be adjustments. This is especially true in the Cinematic universe: Tony Start was originally a Vietnam creation, but given that Vietnam's decades back and they still wanted reasonably young and awesome Tony Stark, they had to update him to an Afghanistan-war-type background.

As far as Thor and female is concerned, hey, Wonder Woman held the Hammer, Thor's held the hammer, Beta Ray Bill's held the hammer, Storm's held the hammer, Thor-As-Frog has held the hammer, what matters to me is whether they're THOR when they wield Mjolnir. As long as they're still clearly Thor and they do Thor's job in a way that Simonson would approve of, I'm cool.