She is still fertile but if she did get pregnant the risk of down's syndrome and other congenital disease greatly increase after 40. There are other options for her beyond the birth control pill such as tubal ligation, IUD, and long-term birth control such as Norplant. With that said the issue for you is to get to the root cause of her wanting you to pull out. It could be a fear of pregnancy or it could be something else. You will not know until you ask.