i'm 46 and have been vegetarian for 25 years. it is possible to weight train and not eat meat, i do it and have made steady gains doing so. i use aas, trt amounts with an occasional 'blast', so not coming from a natural perspective.
i feel good more or less all the time, am rarely ill and if i am, it doesn't often hang around for long, am always lean and my cholesterol, b.p. etc have never been an issue.
protein isn't hard to get in, eggs, yoghurt, nuts, cheese, beans and rice etc and it's pretty easy to get your needs (mine have lessened over the years as i've come to the conclusion we don't need as much as we've been led to belive) plus the fact i cause no animal's death is soothing to my ethical outlook, though i can't bear the holier-thn-thou kinda vegetarian/vegan who preaches. each to their own etc...