I dont think that the age matters. What matters is that they have all the needed shots. Most groomers will not groom your pup if they have not had their first sets of shot/incl. rabies
And I just let Meka's hair grow out for the 1st year. The only time I shaved her was at 5/6 mo's because her hair had matted really bad.. I keep her cut very low now, only beacuse the longer coat is a lot to maintain.... Hope this helps
