My male was about 4 months old when I got our little girl, although they're 2 months apart in age. They are the very best of friends, but each has retained their capacity for human bonding, too.
There's an old American commerical - perhaps you've seen it? - about potato chips: "Betcha can't eat just
one!" Yorkies are like that
. One is good, two is MUCH better, and I would imagine 3 or more would be just that much more merry
.
Go for it! Why wait? You *know* you're gonna do it anyway
.