It sucks, basically. Gender’s a load of made-up rules about what people must do and what they shouldn’t. It’s based on your biological sex, but it is in no way the same thing. It’s socially enforced through shame: this affects boys/men as well as women and girls, and hits women a whole lot harder.
I’m not particularly unfeminine, but I have no “gender identity”. I’m just me! Women & girls spend a lot of time fighting against gender expectations – it’s nonsense to say we’re all comfy & happy about it. We’re being judged all the time on our gender performance: are we too sexy, not feminine enough, not pushy enough, too determined, not friendly enough, too ingratiating, too domesticated, not houseproud enough…? I don’t believe there is an end to that list!