App calculated 6weeks 4 days but smaller than 6weeks on scan

hi. just went to see 1st appt yesterday..based on app, mine is 5weeks plus but radiographer say its abt 5 weeks, 2mm with heartbeat flickering.. she say overall its normal. i think yours is normal too, almost 2mm.. dr never tell me EDD, need to wait next appt, which is 4 weeks later, when bby 9weeks then he will tell EDD. He said 5weeks too early to tell EDD..