Any input on bpd measurement? :S

[Al4321]

We had a scan yesterday..Thought I was 13+3 have had previous scans..Know around when I ovulated could be a a day in or out but deff not a week earlier. Anyways had scan yesterday babys CRL measuring perfect 13+3 so is femur bone, but they measured the head and the BPD measurements which apparently more accurate was 5 days ahead putting me at 14+1 So how far pregnant am i? what do I go by??

Thanks ladies