how could Leonidas be the MC's grandfather?

[Dweller Beyond the Threshold]

Leonidas was already 60 when he died in 480 at Thermopylae. Since Myrrine is supposedly his daughter, shouldn't she be at least 10 years old by then (and given how people of that time give birth really young, having a child past 50 already seems way too late)? Then that would mean she should be 60 years old at the start of the Peloponnesian War, but her design doesn't reflect this age, she looks more like in her early 40s or at the most late 40s.

It just seems to make more sense to make Leonidas the MC's great-grandfather. Or am I missing something from the story?

[conr]

perhaps leonidas' bloodline looks naturally young, lol

[Darth Wadewilson]

may be myrrine got some of that ageless features from alexios' 'father'?