Tbf I think first puberties boon ends for most at 25 and then there begins a subtle lifelong decline to the endocrine system starring around 25-30 that is exponentially worse and down regulated by 60 for most? It kind if makes sense, I think, that without modern medicine a lot of people would not he expected to live to a number such as 90. So 30 is at least ⅓ of the way there. I can kind of see why 36. Buy I'm just trying to come up with random justifications for the number idrk anything