Luna had her first puppy cut at 5 months... her hair was just too messy and was matting awfully, so I decided I was going to trim half an inch myself... I will have to add she ended up with an inch long hair
because she was moving too much and I was not fast enough, LOL, she looked odd a couple weeks, but after that, BIG difference... I am glad I cut her hair, specially now that it has grown back again and it is much silkier and does not mat anymore... Sometimes I think you HAVE to get rid of the puppy coat!
My personal advice?? If are you doing it yourself, BE FAST!!!!
She is 9 months now, and as cute as can be!