When I was training my instructor said to me at the end of one lesson "I expect you'll go solo next week". I thought (worried!) about it all week, and made an absolute hash of the following lesson! Didn't go solo and went home very disappointed.
I did something very similar; got so worried and excited I could barely drive to the airfield, let alone fly. A lot of instructors don't tell people until they're about to send them off; seems like that might be a good idea for people like us.
Just remember...
What do you do now when you get in the aircraft? Fly.
What will you do after you've done your first solo? Fly.