Is my YU-GI-OH agent fairy deck any good, i really need suggestions.?

If you are not going by the Limited and Banned list, you're OK. If you are, you need to take out two of the Marshmallon's. I would also remove one of the Master Hyperions and replace the three with three Hecatrice (as an easier way to get your field spell card to your hand. I would also replace Return from the Different Dimension (I'm not really a fan of that card) and the two Smashing Ground with Field Barriers.