I am sure he will be fine Flyball is generally trained one on one, other people may be holding dogs near by but they would not actually be running. most new dogs are distracted easily so dont worry about it. the first thing you should be working on anyway is Re-calls someone holds your dog you run and call them. this should be on the flat lol untill the dog has a very reliable recall, jumps should not be added in, then they should be added one at a time. make sure to bring something very enticing to him lol does he like to tug? if you take 3 long strips of fleece(old cloths) you can braid them together for a tug. a tug is one of the best ways to go because when the dog has the tug you are in control, when you use treats the dog can come, but its so easy to give them a treat then they run off before you an grab them.

and of coarse have fun!

PS. you may want to bring water for yourself lol