I started with track days when I was a kid. Something like 7 or 8. 125CC dirt bikes, but still, it counts.
No, you don't need to know how to get your knee down to have fun at the track, in fact, my stepfather's friend and I are the only ones I've seen do it.
There's no reason you shouldn't ride your bike there that I can think of. I always do, but if you've got the money for a second, track-only bike, I say go for it.