cervical length experiences

hi ladies! hoping to get some input on your experiences.

I have a short cervix from 2 previous surgeries and am now 18w3d with my first baby. because of my history I've been seeing a specialist and getting my cervix measured since 16w3d. no cerclage or progesterone supplements yet, everything is just preventative monitoring at this point.

at the first measurement I was 2.6cm which they told me is right above the red line of concern (2.5cm). I went in for my second measurement today and was shocked that i measured 3.8cm.

I've been trying to find instances of a cervix getting longer but there's not much out there. it's wonderful news if correct, but I'm just worried the ultrasound tech today could have been incorrect. the imaging looked better to me the first time I got measured: I could clearly see the cervix and what she was measuring that time, but this time I couldn't tell how she was determining where the cervix ended.

has anyone else experienced anything like this?