Nub theory

Liz • Our first baby 🤰🏼is due February 2019!!! Mom to a baby bulldog 🐖. Married my high school sweetheart. 💍 This year will be 12yrs dating 2 married. ♥️

Was exactly 13 weeks but they said I was measuring a few days early 12+4.

Tech gave us a guess but want to know what you think.