I had to interview four surgeons before I found one that would do a double. It's different in the country. I was 43 and fit so was in a good position as far as enduring the procedure.
My advice is that anyone contemplating this gets involved with a counsellor and has some robust discussions with them about it. In the end, the surgeon who I chose rang my counsellor to confirm that I had given the matter proper consideration. Which was a bit patronising and demeaning, to be honest. Like, do you really know what you want? Yep, I did. I didn't want to go through the whole process twice when I was fit enough and informed enough to do it once. Sometimes you have to tick the boxes.
Mind you, I had tissue expanders placed at the same time. I wouldn't recommend it--had nothing but trouble because my body hates the intruders. Everyone is different.