Cervix Length!

So I had an ultrasound today and they checked my cervix. She said normal is 2.5-3.0 but they like to see it at a 3.0. Sitting mine is 2.7. When she pressed on my belly it’s 2.5. She said they might want to follow up in two weeks to check it out again. Has anyone dealt with this? I thought my length was normal!