Definitely check out and monitor the FFS subforum. bound to be somebody with a similar situation eventually.
My adopted mother (who was trans) came out at 57 and after her orchiectomy , ended up having issues with diabetes, blood clotting, and strokes. Unfortunately she never was able to meet the requirements for SRS or any other surgeries before she died in 2013.
That being said, if you are healthy with no real health problems at age 72, I imagine there are surgeons who would be willing to operate. I think they often require EKGs and such after age 50 or so but to each surgeon their own.
Good luck to you!