Is it normal for people to quit before the game even really starts?

Hello all, new(ish) brotoss here..

So, I just finished playing my 5 placement matches and was placed in the platinum league. However, I don't think I was quite deserving of that. 3 out of the 5 games I played people quit either immediately or not long after. Is this normal? I don't really mind losing, but I don't exactly want to lose every game because in reality I should be in a lower league haha

P.S.- if anyone wants to play - iTzCheese is my name (and no, I don't cheese. see:cheese