Tony's response mirrors my experience exactly. I've spent hundreds of hours on the sim ( AFPD and G3) before flying my parkflyer. The sim training help tremendously as you know instinctively which way to move your thumbs to correct the plane's attitude. However for that first flight - your hands are trembling like jello so its quite a handful just keeping your plane flying straight and doing the standard pattern. The nervousness goes away on subsequent flights.

G3 is better than AFPD in that their planes are less forgiving - the Tower Extra, for example, drops a wing abruptly and practicing on this plane helps you stay nimble on the sticks. This has helped quite a bit as I got close to tip stalling my real plane. On G3, you can bump up the wind, shear and turbulence quite a bit - but it still different from the wild conditions I see at the field. If you can help it, wait for a calm day for the first lesson.