Is 3D ultrasound worth it?

Pink
We have our gender scan ultrasound scheduled with my regular OB for 20 weeks (which is 4 weeks away) they will also be doing blood work and checkups for any abnormalities with the baby at this appointment but I found a place that can tell gender at 15 weeks with 3D ultrasound so I made an appointment with them but they charge $80 minimum for the scan which you get a DVD of the entire ultrasound as well. So now I only have to wait another week to find out the gender but what do I do with my regular scheduled anatomy scan? Keep it? Because they will be doing blood work also at that scan but will this be overkill? I also feel a bit weird walking into my anatomy scan already knowing what the baby is lol