Gender at 12w4d ultrasound?!

So i went to an hd ultrasound place to check on my little one after some bleeding and cramping yesterday. During the ultrasound the tech said that baby is cooperating and she would be able to get a look at the gender. So i told her to go ahead and put it in an envelope until my husband and i can look together.

My question is, has anyone been in a similar situation and the gender be accurate?! We currently have an appointment for gender scan in dec 16 and trying to decide if it will be enough to cancel that scan?! Any input is welcome! Thanks!