Don't panic that it's light/late!
My period was about a week late when i got my bfp (had tested before and got bfn), went to my early scan thinking 7 weeks based on lmp but was 6 weeks.. My consultant said based on my cycle lengths, I wouldn't have ov'd until around cd18 so it pushed everything back so even though i was 5weeks+ when i got my bfp based on lmp, i was technically around 4 xxx