Head Circumference

I am 24 weeks and had my follow up anatomy scan yesterday (she wouldn’t cooperate the first go around). She measured normal for everything except her head is on the smaller side. It was measuring at 22 weeks and 2 days. The tech didn’t seem to be worried and said she felt she was just a smaller baby with a “small noggin.” However, I can’t help but worry due to that fact that she’s in like 4.54 percentile. That seems a bit small. Apparently it was measuring smaller at her 20 week appointment as well but she didn’t say anything. Anyone have this occur?