Katniss actually said that if not for the existence of the Games and Panem's shitty state in general, that she, at 17 years old, could possibly be married and pregnant. Full-on teen mothering it with her dandelion in the spring if Panem could chill out for a sec and stop killing children. And then she proceeded to fantasize about Peeta and his child safe in the meadow. This thought alone gave her one of three nights of restful sleep without drugs post-Games during the series (the other two being when she was in Peeta's arms).

And yet when the Games did end permanently and Katniss indeed went ahead and married/committed to Peeta and had a family with him at about 30 years old, some people still did a surprise Pikachu face and complained it was out of character.

WHAT MORE DID SHE HAVE TO DO TO FORESHADOW THE ENDING?

The whole passage in Catching Fire

I know my face is projected in a tight close-up on the screen, but I don't make any effort to hide it. Because for a moment, even I am working through what Peeta has said. Isn't it the thing I dreaded most about the wedding, about the future—the loss of my children to the Games? And it could be true now, couldn't it? If I hadn't spent my life building up layers of defenses until I recoil at even the suggestion of marriage or a family?

is very interesting when you think of the implications Katniss is making. It could be true? If she hadn’t guarded herself? She could be married and pregnant at seventeen?