Very interesting topic.
I live on a small farm and we still have some old stuff in the barns reminding us of the years in agriculture from more than 50 years ago. With regards to farming I feel myself quite useless to be honest without my husband's knowledge.
Since I'm already past 40, I would not be much use in repopulating... but I could take care of kids. I could do chores even if there wasn't electricity or the machines like today. There would just be a lot more physical work to do.
I don't know how to milk cows, but I suppose that could be learned, like taking care of other domestic animals. My first aid skills are poor, but I'm handy otherwise and could manage some sewing or help with building something.
Lots of hard work! 
I don't mind dirtying myself or doing physical work, but it would mean a lot of adapting.
Another thing would be, if there was a complete chaos around you and you would have to fight for survival. Even if there would not be competition, the need to cooperate would bring me to a new situation of having to cope within a group and possibly live with a big bunch of people more closely together.
In fact - the best way I could be prepared for this scenario, would be having my husband around. He's very handy and would manage to take care of many problems.