Hard to beat Felio's advice...
From another old timer (age-wise; 45, but just started racing late last season), welcome. I didn't listen to good advice, and I started on a 600. Tons o fun, but would have been better starting on an SV or a 250. (PS, I've got a Ninja 250 commuter for sale if you PM me.) Now I'm riding both a 600 and a 250 (different one), and the 250 is more fun.
Also, I rode track days (classes) for almost 2 years before I started racing. Well worth it.
Hope to see you out there.

