what adjustment should i be looking at if my brush is spraying paint before i pull the trigger back? thanks in advance.

I am by no means an expert in airbrushes, but my Iwata bcs will do that if the needle isn't seated nicely (moved forward) in the nozzle/tip. You can only seat it so much though, the tip will eventually wear out. That is also how I learned that I needed a new tip. Could also be dirty and not letting the needle seat properly. When things are dirty though you usually end up with other spray problems like splatters, not enough spray, no spray, bad spray pattern.
Nothing like a good airbrush with a nice clean needle, nozzle and properly thinned paint.

Good luck.