A couple of thoughts:
First, if you start eating meat your parents may very well be able to tell just from your breath/body odor. Living in Japan, where most of the people don’t eat any real amount of red meat, I can tell you that in many cases your diet makes quite a difference in how non-meat-eaters smell you. (Sounds odd, but believe me it’s true.)
Second: I’ve never seen the phrase ‘you need steak to grow’ on this site. Not even once. You sure you’re not confusing us with some other place?
Third: What are your goals? Do you want a professional calibre physique? If so, then yes, you need meat. With all due respect to vman, neither Pearl nor Cahling built their physique on a veggie diet. Once they were big enough, they maintained using it. Big difference.
There was a thread a little while back about this topic, and no one could give a really good example of someone who had built an outstanding physique using only a vegan approach. It may be thoretically possible, but no one’s done it yet.
On the other hand, if you’re just looking to add a little size, then there shouldn’t be any problems doing it the vegan way.