Most agility classes will not take a pup whose growth plates have not completed growing. Patellas need to be seriously assessed before beginning agility. Also be sure the instructor has experience with small dogs in agility.
My Cali is just under 4 pounds and we do agility for about 3 years now.
I hate the name, but check out TDAA ( teacup dog agikity Assoc). Their equipment and meets are got dogs under 20pounds.
__________________ .  Cali  , and Cali's keeper and staff, Jay No, not a "mini" Yorkie - She loves to motor in her Mini Cooper car |