First advice from one who has been there with bells on!!!
Don't worry, most dogs will be at the same level and those that aren't will still be able to embarrass their owners.
Yesterday my delinquent Brittany and I were training with trials ready dogs and at times he remembered he is young and was a pratt. I was told off soundly for telling him off as we were working on water and I was told that training had to be fun and all bad behaviour should be worked on seperately

.
Go, learn but most importantly enjoy. If you feel he is too hyped then keep him on the lead the first session and just assess what happens, any decent trainer should be able to listen to your fears and give you relevant advice. Most handlers have been there, done it and got the T-shirt so will be supportive not critical.
My delinquent had a training group in June (that included his breeder so no pressure there

) in stitches when the trainer (who owns and handles the breeds only Dual Champion) tried to get Chase to bring back a dummy by interupting his behaviour with a lead thrown near pup. Chase dropped dummy, picked up lead and giving the two fingers he ran around showing off his new trophy

.
Despite all this a few people who know Brits are very impressed with his attitude and if I keep up we will be trialling when he is older.