In cases like these, the 11 year-old can't reliably consent either way, and that's the problem. It's easy to assume that she's better of having the abortion but she can't consent to that, either. Consider if, instead of accepting the choice that was made for her, she decided that she wanted the child she was carrying and considers the baby's abortion the murder of her child. What kind of crime would that be against her, compared to the hardshiop of forcing her to carry a child she doesn't want?
You're right. The ability--or lack thereof--of an 11 year old to consent is a big problem. But I am much more comfortable with that decision being made by her parents than by someone who doesn't know her and just wants to impose their ideology on her.
Well, that might kill her. She's eleven.