"What if the girl is too young to have a baby? Isn't abortion the best option?"
If you're too young to have a baby, maybe you're too young to have sex. With sex pregnancy is always a possibility, and even if you're not having sex to get pregnant, you still can.
If she's too young to be having a baby because she's still a teen-kid herself, if she doesn't realize it then, she will later that she aborted her baby, not just simply a clump of cells. Abortion brings a tremendous amount of guilt. So really, abortion isn't the best "option".
For parents, if their daughter comes to them, saying she's pregnant and wants to keep the baby encouraging abortion is not cool. She needs your support throughout the pregnancy. Don't ask her to abort your grandchild. Don't ask her to willingly step into something that will give her a lifetime of regret and guilt.
And if you honestly don't want her to raise the baby, suggest adopting the baby out. But if you tell her to adopt the baby, she will probably pull away from the idea- more than likely she already thought of it. Just ask her if she's considered adoption. She can pick out the family, and even do an open adoption. But if she wants to keep the baby, support her. It is her baby, and maybe she doesn't want to let someone else raise her child. If she's willing to be the mother she needs to be, she shouldn't be forced to give away her baby.
I don't see how abortion is the best option. Maybe it may feel like it, but remember, it's not a kidney you're having removed. It's a living little human, with a heart beating just as yours.
Remember, every abortion is: one more heart that was stopped, two more eyes that will never see, two more hands that will never touch, two more legs that will never run, one more mouth that will never speak. And that is for every single baby, including if you're too young to be pregnant.