It sounds like your not comfortable with this decision and you need to be.
As predicted my sister is not talking to me. But now that some time has passed I still believe, FOR ME it was the absolute right decision. I don't think I would have handled it well nor my own family. If this means that I lose my sister so be it. I would have thought she, as a sister, would understand my decision and that because we love each other this would have been ok. Apparently not.
I hope you are not getting pushed into this. If you are think long and hard. It's a BIG decision and one that may cause heartache in the future. No one........... not even family....... has the right to take over what is rightfully your own. Your body, your heart, your children, your eggs.