Like with Runaway Teen, only give her one helpful trait, maybe two to ease it up.

Make some means of her being pregnant pretty soon after the start of the game. I'd start with her and an adult boyfriend, and a shower, and uh. You're gonna need the NRAAS whooer mod (I think that's the one) and to turn on teen pregnancy, download some body morphs to have her not be a floating head. She's got to survive on an empty lot in a new town away from her parents and damaged reputation, with no house and a baby on the way. To make matters even worse, her parents have kicked her out and the guy' done a runner/died/some kinda gone. I don't know if this has been done before or whatever, but y'know, I'm doing it too XD (is it in the right category? first challenge)