Previous Leep & current pregnancy

So 2 years ago in November I had a Leep procedure done. I didn't worry too much at the time about pregnancy. I knew we weren't going to try right away, or at least until I had some good paps. Well anyway we are 12 1/2 weeks pregnant. Now I'm so, SO worried about my Leep procedure and cervix strength. My doctor said I would have a sonogram at 16 weeks to measure cervix. I started worrying that maybe 16 weeks is too late for a measurement. I called today to talk to a nurse for some hopefully peace of mind. She said 16 weeks isn't too late.  I guess I am just worried my cervix needs checked before then. My doctor told me before that typically the issue after a Leep is scar tissue via weak, but I can't help but worry. Any positive stories?