finding out gender day before 17 weeks?

So I will be 17 weeks on Christmas <a href="">Eve</a> 😊 so I was thinking of going to one of those elective ultrasound places on the 23rd to find out the gender and then surprise our parents on Christmas with some sort of ornament or gift that reveals the gender. 
So my question is...I know it may be a little early, but the ultrasound place says anytime after 16 weeks, so I would be the day before 17 weeks...I am nervous it would be too early. Has anyone else found out easily that early? 
Also, what's the best way to reveal on Christmas?! We would find out the day before xmas <a href="">eve</a>, so we would be on a time crunch which is why I need a plan in advance. Anyone with advice would be awesome!