I know you are excited, but you should be training him
not to jump on and off furniture.
Yorkies, like other toy breeds, are prone to luxating patellas (slipped knee caps) which can be caused by jumping on and off furniture. They can also tear their ACL pretty easily. Surgery to repair knees runs into the thousands.
Get some pet steps as the others have suggested.
Here is some information on luxating patellas.
Luxating Patella: A Knee Problem in Dogs