Just watch this and hopefully come to the right solution: https://www.youtube.com/watch?v=0Al330i1skc https://www.youtube.com/watch?v = wZJfJ8bWbaI
I have been a vegetarian since the age of 14, everyone said that it is very unhealthy, that I am a growing body. Everything here consists in a certain diet that you need to compose yourself (look on the Internet), or still go to a nutritionist. Together with my sister (she is a nutritionist) we made a balanced diet for me. I can definitely say that veganism / vegetarianism does not harm health, but on the contrary is beneficial
I cannot recommend that teenagers under 20 give up anything. I stopped eating meat at 21, when everything seemed to have grown and the need for animal products gradually decreases. I don't know how rejection will affect at an earlier age, but remembering myself, I can say that I really wanted meat and milk when I was growing up. Perhaps a growing organism requires. There are many negative examples where giving up animal products causes bad things, so for now, eat everything, please. With age, the desire itself weakens, believe me!
As for the advantages of rejection for an adult body, there are a lot of them: you will be slim, beautiful and young for a very long time. Therefore, for now, eat and grow, and therefore grow and refuse to your satisfaction. Good luck!