I got Roxy very young too, she was just over 7 weeks and the last of a litter of 5 to leave the mother. The only problem we had with her was trying to get her to eat, (And a mild hypoglycemia episode) even though we got food from the breeder I still think she was very sad at leaving her home but after a few days with loads of love and attention she realised she was going to be very loved
She just needed time to adjust.
The lady we got her off has been breeding Yorkie's and Maltese for years and when we went to see Roxy at 5 weeks she told us call out in 2 weeks to pick her up!!
I would wait longer if getting a second furbaby but there definately isn't any behavioural problems with Roxy.