Just be there for yourself and your own enjoyment - make a point of having the biggest smile at the end of the day rather than the fastest time.
I did my first track day with Suzuki Race School as I didn't want to use my own bike - so can't really advise. Though pessimistic, Northy's advice is also very realistic. Strip what you can from your bike and carry some basic spares if you can - just aim not to use them.
