Confused about how far along I am!!?

So I was hoping someone might be able to clarify this for me and I’m sorry if this is a stupid question but how far along am I? My last menstrual period was 22nd April but i have really long cycles and probably conceived when i ovulated (21st May?). Surely this would only make me just over 2 weeks pregnant but according to my app it’s saying 6 weeks pregnant.

Do you have your 12 week scan at ‘12 weeks pregnant’ or 12 weeks from conception?

Thanks so much in advance!