Serigating for sister?

Tamara
My sister wants to have children but cannot got pregnant. I haven't been feeling well for 3 weeks and am showing signs of pregnancy. She keeps joking with me about giving the baby to her, we had a discussion and I'm wondering if its right. I honesty think ill be okay with my child calling me ain't and not mommy. It would make my sister happy and would help me because I'm only 17.