Re: Meat when you're young, vegetarian as you get older?
I tend to think that a diet of meat isn't good at any age... I mean, you listed your own health problems as an example. A younger body may need more protein since it's growing and younger people tend to be more active, as if that's necessary plenty of protein can be found in nuts, seeds, hemp (ie. hemp protein powder), chickpeas, lentils, and some beans. Sea algae like spirulina are excellent protein.
A well-balanced vegetarian diet supplies you with pretty much everything you need at any age. I'd just make sure to supplement with B12 since that's sometimes tough to get through vegetarian foods. Some people believe that B12 can be manufactured by the body, or you can get enough through royal jelly or spirulina... that hasn't been my experience though.
Honestly, I thank God I went against my parents wishes and became veggie when I was 8. They're meat and potato eaters, and overweight with bad memories, eyesight and who knows what else in the future. Maybe because I became vegetarian at a young age... but I've never had a craving for meat. It's always repulsed me. Ever wonder why parents have to force their babies and toddlers to eat meat and TEACH them to like it (often disguising it with breadcrumbs and calling them nuggets or whatever), but don't have so much of a problem getting them to eat fruits?