I Think I Have A Problem With My Penis Because

I think I have a problem with my penis because in 17 and my penis is usually around 1 to 2 inches, sometimes it can be 4 inches and when erect it's about 6 inches. I'm afraid to go to the bathroom because my penis is most likely going to be small and that will ruin me and I've just started dating a girl and if she finds out I don't know what will happen. I'm to scared to go to my parents because it's really embarrassing to talk about I need help please