You have to do what is right for you. If you feel that having a double mastectomy is what you need to be able to live your life more freely, then maybe that is what you should consider. I am a bit biased though! I was diagnosed with extensive DCIS in 2003 at the age of 35. It showed up as a 6cm (yep cm not mm!) area on the mammogram and the doctor suggested having a mastectomy due to its size. I had the mastectomy and the DCIS ended up covering a 9cm area, not 6cm as was shown on the scans! As I had the mastectomy, I didn't need any radiation which was great and it hadn't spread so I also didn't need chemo. I had a TRAM flap reconstruction and ended up with a lovely soft breast which looks great.
On the flip side, I was diagnosed for a second time in 2010 (7 years later) with BC in the other breast! This time it had escaped the milk ducts and was invading the breast tissue. It was only 2.5cm in size but due to my history I had another mastectomy. The reconstruction this time was a Lat Dorsi one and it feels a lot firmer and not nearly as comfortable (looks great though!). I had to have chemo this time as it was invasive, although my lymph nodes were clear.
If I had had a double mastectomy at the time that I was first diagnosed, I would have been able to avoid going through it all again and avoided chemo....all very well in retrospect but at 35 I didn't feel ready to have both of my breasts removed when there was nothing obviously wrong with the second one! I had a few relatives in my family with BC but when I was tested, I don't carry the BRCA 1/2 mutations so am not at any higher risk than the general public. My weight is in the normal range, I'm not a smoker or heavy drinker and generally live a healthy lifestyle so I have no idea why I have had this horrible disease twice.
I wish I had made the choice to have them both removed at the first instance, but I didn't. I wasn't ready to then and I really believe that you need to do what feels right for you.
Good luck with your decisions.....they are never easy ones to make!
Hugs,
Louise