Agility is great fun for both dogs and their handlers, and some elements of agility will be included in all classes. The dogs require a good level of general obedience to take part in agility as they need to stop, go, jump, come, etc. on command. The level of agility undertaken will be modified for puppies and young dogs.
Your trainer will introduce agility elements a bit at a time to you and your dog, some dogs take to it more easily than others, the tunnel, for example, can be more of challenge for some dogs at first. Agility is about trust as well as obedience and fun. Even if they are not sure at first, most dogs love tackling an agility course at speed.