Hi and welcome from me and my boys.
Not heard that about flyball before, think it would depend on the dog and how they are handled at home, be interesting to hear what other people think.
Solli (11½) and Whisper (nearly 8) love their agility classes. Solli is enthusiastic about obedience classes, Whisper on the other hand only gets excited when doing recall or scent discrimination. Caleb (approx 6 months) is coming along nicely on the obedience side of things and making up for having no training at all before he came here a month ago.