Firstly, congratulations! Second, you know you didn't have to wait until you had gotten a black belt before you started posting here, yeah? Thirdly, which system? I'm assuming by the name "Combat Ju-Jitsu" it's a modern Western one, yeah?
Congrats!! Isn't 4 and a half years really quick? If so, double congrats!
To be perfectly honest I'm not 100% sure, it's my sensei's own style. It's sort of a cross between Japanese Ju-Jitsu and and some other type he taught in the military. I really should know more, I admit, but I really don't know.