ultrasound picture ❤

First ultrasound today! According to my last period I'm 8w2d but she said I'm measuring at 7w5d so it'll be up to my doctor to decide which to go by. She said they aren't allowed to let us hear the heartbeat (which I thought was strange) but she did show us it beating and it's about 160. Any guesses on the gender? I know it's early. Also I was told that we won't have another ultrasound until about 20 weeks which is when we will find out the gender, is that normal?