I've done a few track days in my car and autocrossed for 4 years. If doing a track day on a bike is anything like in a car, you'll be hooked instantly. Whatever you do, go there with the state of mind that you're going to learn, not that you know what you're doing. In the few track days I've done, I've passed a few people who thought they knew what they were doing in S2000s, Mustangs, and even an NSX, in my 96 Dodge neon. It was prepared for stock class autox at the time, but shouldn't have been able to hold a candle to any of the above cars with anything close to equal drivers. You'll learn a lot more if you go into it with the mindset that you don't know what you're doing and want to learn than thinking you do.