Making appointment..

My insurance is switching my provider so starting the 1st I'll be placed with Kaiser. I just had my final appointment w my current ob and he wanted me to make an appointment for my anatomy scan the 29th. But unsure if I should go or wait till I get my new ob to do it ? I'll be 19w6 if I do it on the 29th if not I'll probably have to wait till 21w ? What should I do ?