I have been playing on this server since last year, and I play on it a lot. But for some reason, I am still in grade 8. I have been grade 8 for almost 7 months. Also in chat my name looks different. I dont have a number or "sophomore" next to my name like everyone else does. Can you please help me?

I have been playing on this server for at least a year and i have been playing every single day. But for some reason, I'm still grade 8 and I don't have the word sophomore or the age next to my name like everyone else does. Does anyone know why I'm not ranking up in grade?