The nerves you have now are normal, it gets worse once you are on track with a dry mouth, so drink lots of water.
Its your first Track day, you WILL be crap, but the knowlege you walk away with is priceless.
bravado will will put you in a world of hurt.
There will be other riders on all sorts of machinery and skill levels
Just worry about what you are doing.
Its not a p1ssing contest, and its not racing.
If you listen to the instructors this will not happen.
If you or someone in the group does bin their sh1t, the session will be red flagged and spoilt for everyone.. so try not to be 'that guy'
Medics and Ambo on site.. you will be in good hands with good drugs.
This is why we do it.. and keep coming back for more,
its the best fun you can have with your clothes on.
Be an attentive listener,
talk to the instructors,
ask for help or advice,
take on board their comments, they do what they do because they are the best in their game.
Pay particular attention to the body position exercises, then practice practice practice that for the rest of your life.
Utilise the no gears/no brakes sessions to full advantage and everything will become a billion times easier, and alot faster alot sooner.
dragging a knee is a byproduct not a goal,
some of the best riders can do a whole race season on one set of kneesliders.
'trying' to get your knee down will end in tears.
learn to corner the way they and it will probably happen (happens too much on the cbr250 with its low pegs) but for a lot of people, getting their knee down is actually an indication of a bad, forced riding position, not skill or speed.
Your goal should be to-
'Kiss the mirror'
'Bite the handgrip'
'Lead with your eyeballs'
'Point your toes in the direction of travel'
^Those and many more keywords Bernie Hatton will teach you.
Enjoy... be prepared to never want to ride on the road again.