I understand your concern. I am 76, had a mastectomy in Nov. '21. I am waiting for reconstruction. One week following surgery, I had several weeks of the spacer being filled and then followed by radiation and more chemo.
The recovery from surgery was fine. The drain was initially tricky, but I was able to manage by myself. I understand that there are laniards that can support the drain while showering. I wasn't aware of that when I had my drain so I taped the drain to my waist.
I also had no difficulty eating, no dietary restrictions. So I ate healthily including extra protein and plenty of fresh veggies and fruit. I also slepted when I was tired and exercised when I could. I walked up to 4 miles a day before surgery and got back to that distance within 3 weeks. Good luck with your surgery and recovery. I really hate that people dismiss us because of our age.