Confused how far gone I am?!

I went for a private skan and measured 8 weeks then had another at 10 weeks then I had my nhs skan at the hospital and they said on the 24th jan I was 12 weeks so today I should be 15 weeks. Went for my gender skan witch was the same lady who did my 8 and 10 week skan she said I’m measuring at 14 weeks 2 days but that measuring perfect with the 8 and 10 week one I had. So who do I go with the hospital or my private skan? 5 day difference between it I’m so confused and worried :/