The price seems a bit high to me but to make an educated guess on worth, you need to say what extras are included and their condition. For example, electronics, helm cover, cabin canvas etc. The trailer may be worth 1000 or so depending on age. Condition is hard to tell since these trailers corrode from the inside out.
My 2001 with the 150 SX and full canvas in good shape, a decent trailer, extras like helm cover, PFDs, radio, GPS, wash down, fresh water hose, no pulpit, no tabs is probably worth about 16 to 18K. Some smaller boats like this model appreciated a bit when gas was close to 5 bucks. Now they have stabilized.
In mu humble opinion, many boats 'look' like they are pristine especially if it is your first. A marine survey is the best investment you can make. These Grady's often have transom moisture issues and that needs to be checked by a pro.
Best of luck with your endeavor