Margo, welcome. Choosing between a lumpectomy vs a mastectomy is a big decision. You may be interested in this related discussion:
- Preventative double mastectomy https://connect.mayoclinic.org/discussion/preventative-double-mastectomy

If I may, I might suggest discussing the pros and cons of mastectomy vs lumpectomy with your surgeon. Ask questions about the possible benefits vs risks. Does a mastectomy mean that you will be "done with it"? While that may seem logical, is it true in your case? Your surgeon can answer those types of questions tailored to your preferences.