Anyone is well advised, not to expose a young Dog to others, until the standard protective inoculations have been administered.
Having said that...
Age shouldn't be a factor in choosing when to go to a Groomer.
One wants to keep his animals looking good...ok.
Ambient Temperature may be a factor for shortening their coats.
One may not have the time to do extensive Grooming themselves.
Grooming is at 'your' convenience, use a practical approach
Most of our animals love and want to protect us.
I know that My Male Sneakers is a TOTAL terror, when someone approaches me, while we're out and about, however...
All I have to do is "convince" whoever (groomer/vet tech) to take the Leash and move him away from me. He settles right down and goes along with them.
Try that !