Ima do mine at 28 w I'm 27w3d
I had mine done at 27 weeks and he looked so perfect.
But the office I went to said between 27-33 weeks is the best time.
I got mine done at 33wks and it was so perfect his features where so clear and he was fully developed with hair and he was blinking and sucking his thumb it was amazing. But i have seen a lot if women on this forum have theres done alot earlier. They say you don't want to wait to late though because they get so big its hard to get a good image and if you have to much fluid it can also affect the pic.
i juss called a place today nd the guy said the best time to get the best results would be between weeks 26-30