fundal height...

Brittney

I'm 28w3d today I had a ob appointment, he said my fundal height was measured a little over a 30...what is fundal height?? Is mine normal?? I should also add that my original due date was 11/22/17 and is now 12/1/17 because my baby was smaller at the ultrasound. Will she arrive early?? HELP! FTM...