Head Measuring Small

Ni
We were sent to a specialist because at our 21 week anatomy scan our baby girl was measuring small (in the 7th percentile). They said it was not concerning because my husband and I are also small, but they just have to monitor her growth. We seen the specialist yesterday and they said she is still measuring small (27th percentile) but that she is within normal range. They did say her head is measuring a bit small as well so they want to follow-up in 4 weeks. She didn't seem very concerned and repetitively said its not concerning yet and that everything else anatomy wise is great. She said because she is breech she doesn't have the right pressure on her head that most babies do and that once she flips over it could measure correctly. Also, she wasn't in a very good position either. She also said once she seen me in person that I have a small head as well and it could be genetics. I'm trying not to worry but the thought is scary that even with all those justifications something may be wrong. Has anybody had experience with this? Thanks ladies!