Sorry I didn’t actually see that part of your post I guess. That is interesting.
“And I’m not sure what you mean, are you saying some hold the HALACHA is a 14 year old shouldnt wear a tallis gadol!?!?”
No, I’m saying that EVERYONE holds that anyone at any age isn’t halachically required to wear a tallis gadol. The minhag is to avoid it, the halachah is that they still have to wear a tallis katan. Those who say you should wear before marriage still don’t say it’s halachically required.