I'm 24 as well, and honestly I couldn't do it.
Not to say you can't or shouldn't... just giving my point of view.
Understand that her kids will always come first. Also, it'd be good to know how involved the kid's father(s) is/are. Are you looking for a short-term gf? If so, walk away, the kids will just complicate that issue. If you're looking for something long term, keep in mind you may become a father figure to her children.