I have a 15ft glasstream bass boat and All the sudden the other day it is stuck in forward and I can't put it in neutral or reverse and idk what's wrong with it.

With no more information than you gave it isn't possible to say. Gears are a function of the motor and not the boat. I would suggest disconnect the control cable at the motor and try to shift it manually. That way you can tell if the problem is in the external linkage or in the motor. At least that is a good place to start.