Margaret "also Peggy, thank you" Carter, the Second (because why should only men get to name their children after themselves?), was born in 1960. This is kind of an inconvenient year to be born in magical Britain, if you want to avoid having an interesting life, but she has desperately wanted since before she could walk to have as interesting a life as her mother, so.
By about 1980, a normal person would probably be deeply regretting that wish. Britain is at full-blown war, her mother is five years deep in some sort of insane undercover assassination plot halfway across the planet, all her hard work painstakingly not being an asshole to her housemates as a teenager has gone completely out the window because she lost her temper and murdered one at graduation, and she's subsequently spent the first few years of her arguable adulthood fighting an increasingly losing battle with a tiny array of allies who are mostly idiots mostly not much older than she is and also mostly don't trust her because she's a Slytherin.
But she's actually having a great time, all told. She gets along just fine with Edgar Bones (who is, despite being terrifying in single combat, constitutionally unable to personally dislike people), and Alastor Moody (who trusts her even less than most people do but this is no more and no less than he trusts anyone), and Emmeline Vance (they've actually sort of been friends since like second year via Quidditch). She gets into shouting matches with various Marauders every five minutes while not actively fighting Death Eaters with them, but this is mostly fine because they are actively fighting Death Eaters basically all of the time.
When the war ends, she's happy for about three weeks and then she's bored and restless. Turns out if you spend your whole life carefully turning yourself into a perfect replica of someone who skipped half her classes from 14-17 to get into fights, passed all her NEWTs anyway, decided to get a Muggle university degree, got into Oxford with only like 10% forged credentials, and then promptly dropped out to go stab vampires in occupied France, this is not a recipe for handling peacetime with enormous aplomb. So she goes and finds her mom, and spends six months arranging to have a half-hour coffee date without breaking her cover.