I think the older you get the more risky it is to take super physiological dosages of steroids to begin with, and tren is known to be one of the worst when it comes to effecting health. Some people with great genetics who have lived healthy lifes could probably run tren in their late 40's and suffer no long lasting side effects, others may not be as lucky. I feel like personally it's probably a good idea to try to avoid harsher steroids somewhere in the age group of 40-50.
I guess one question to ask your self is could you obtain a physique you are just as happy with using safer compounds, and maybe dieting and training harder. If you need tren to get the physique you want is it really worth the possible risks or feeling paranoid about the decision. I feel like testosterone and hgh can produce some pretty amazing results, and then their are still other things someone could add in like primo or even anavar if they needed more. Also at least you could look good and feel good using other steroids except tren, the side effects of tren to me aren't worth it. Also no normal person is going to really notice a huge difference when looking at you on a tren cycle vs a normal cycle unless they are a bodybuilder. I'd go the safer route, good luck on everything.