"Short" cervix?

McKenzie
I don't see my OBGYN until 2/28. The ultrasound I had today (2/24) was at an Imaging Center to reveal the baby's sex.My first pregnancy, at 20 weeks, my doctor told me I had a short cervix of 3cm/30mm. At the time, it was only a minor issue and I carried my daughter to 39+4.Today I am 15+3 and my cervix measured 2.2cm/22mm. I asked her to measure for me.I've tried to research and read, but I'm curious if anyone else's cervix has been this short at 15 weeks? I'm anxious to get my doctors opinion next week.