Hm, very few women ever achieve the level o f strength an athletic man can, that's hard fact. Another ugly fact in the body building community is drug abuse to achieve mass..very dumb and dangerous, causes all kinds of health and sexual problems for men and women. So that kind of perosn should not be brought up on these issues unless it's proven they are "natural", exceptions always exist, sometimes though it's due to health problems
hm interesting character idea that: character's size and strength due to some illness like acromeglia, maybe questing to pay for cure...?.
For fantasy campaigns it's fine if you have a Valkyrie, your campaign doesn't have to be like Earth at all (look at drow for instance, their females are bigger than males).
If you are trying for Eaeth realism, it's extremely rare for a woman to approach the mass and raw strength of a man. A woman's more likely to be a sabre, rapier or spear user, than an axe user (plus magic of course). Go use some of the heavy weapons a bit and see why mass and raw strength are important, and why they are not the "dumb" weapons folk tend to think (well, if you want to
survive using 'em it takes skill).
It's a game, play what's fun and appropriate for your millieu

A rogue conartist or druid with a family would be female characters I'd rather run, but I like dwarf fighter/rogues and Douglas Fairbanks Junior type goodly scallywags as my faves
Also, I like playing old or not very combative folk, when I can get to play, sigh.