Mothers this age( In 35+) have about a 43 percent chance of a c-section delivery compared to a roughly 30 percent chance for mothers in their 20s.

http://www.babycenter.com/0_age-and-fertility-getting-pregnant-in-your-30s_1494695.bc

Cesarean rates are also higher for women older than 35: Mothers this age have about a 43 percent chance of a c-section delivery compared to a roughly 30 percent chance for mothers in their 20s.