i started with a nacra 5.7 myself and switched to F18's when they came to the market. my first cat experience was on a hobie 16. i would not recommend a hobie 16 to you since it is certainly not the most forgiving boat (they pitchpole quite easy). the nacra 5.7/570 is a very quick boat without daggerboards. which is easy for beginners. good decison by the way to start sailing cats!