I've finished my first attempt; with an easy start. I'll try the hard one, too, some time and
@kee, I'm not sure, that anyone can make it so much faster than in 15 year. There is a big difference between hard and easy.
I think it could be a big difference between easy and easy as well. I opened some maps, in fact number 1-10 small maps. The number of children were between 2 and 13, I am pretty sure that you are much faster, with 13 than with 2 children from the start.
I choose the 13 children

I made a save of the one with 2 children as well and will play that sometime, too.
Map 8 small valleys
Start 12/0/13
End 70/0/30
Summer 7
Same time as you,
@Trizeropz !
I couldn't have played that map faster, there were houses ready as soon as one couple could move out. But you could play an easy game faster, with more luck. The girls were older than the boys all the time. At the end I had a lot of young single girls 10-17 years old and only one 9 year old, one 8 year old and a bunch of 6 years old boys.
First picture year 2
You can build a lot the first year with an easy start. I keep an eye on the elder children all the time so I build enough hoses. There are more girls than boys from the start, or at least they are older.
Second picture, year 4Not a very nice looking settlement,but it works.
Girls are older than boys, but at least there are some boys only a couple of years junior. But it's getting worse........

Third picture, year 6...........and worse...........
Fourth picture, year 7 ..................until the end
Sorry I was a bit late with the screenshot, but you can see at the log, that inhabitant number 100 was born in summer 7.