Measuring 4 weeks ahead

Nautica👣😘 • Mom to Beautiful Baby Girls👑 Nova Rae Cooper 👶🏽👣01/06/2016 and Nyla Susan Sarah Cooper 09/22/2020🥰💝👣
I'm a FTM & So Friday morning I went & had my usual check up with my obgyn. && when she measured my stomach She was shocked that I was measuring a whole 4 weeks ahead. I'm 24 weeks But I measured at 28. Is that normal .? Are has this happen to you .?