Stop asking for advice! It's a kid. She already shown how stupid and irresponsible she is. Make the appointment with the clinic and drive her there
If she doesn't want the abortion, call the state on her and tell them you cant support another , baby in your household. The end.
This is based on a situation my sister was in with her pregnant 13 year old 4 years ago, and the steps she took after dd refused the abortion. There is a way around it. She called the state and told them she would care for her dd but not a baby she brought into the home. The state gave the 13 year old a choice -- foster care for her and the baby, foster care for only baby until teen was 18 and gainfully employed with an apartment for one year or put the baby up for adoption.
My niece chose adoption, remained with her mother, and graduated from HS last month. Two lives saved.