I got an ultrasound at my doctors at 14 weeks and it was accurate. Every time they look at her is a girl. With it being that early there is a possibility of it not being clear, but it's just up to you.
I got mine done at 14 weeks and it clearly showed I was having a baby girl, two friends of mine got them done at 13 weeks and both were right also and they were clear.
It is too early. Even with a 3D, it would be more of a guess. It is best to wait until after 16 weeks. 18-20 weeks is ideal. At 14 weeks, baby is still effected by the hormones that develop the genitals. They are often very swollen. Boys can look like girls. Girls can look like boys.
I'll rather wait to get a more accurate info.