Gender ultrasound help

So I live in a complete different state from my family and we arranged what month I can see them as well with the baby shower it’s already difficult that I’m going to be alone for the baby shower since my partner needs to work and today I was supposed to find out the gender and they told me no to wait until May 20 which is a day before I leave to see my family and that’s not enough time to even tell guest “hey it’s a .....” so I was thinking about going to one of those clinic that find out for you but I’m afraid doing the ultrasound would affect my baby or it doesn’t at all ? Advice please