I'm 48, recent checkup states I'm still fertile, Dr. says need birth control, maybe perment, what should i do?

48 and single. I have grown daughter of 25, and a new Granddaughter of 6 months. What if i want to have another baby with the right guy. Females in my family history have had children in their 50ties, perfect healthy births. My own mohter had my baby sister at 48. So do i get fixed permently or leave it alone.