Is this possible

I am a mom of one (she's 8 months) I recently found out I'm pregnant again my last AF was jun 30- July 6 according to the app I ovulated on the 17/18 I got a BFP yesterday at 9 dpo I believe it would be and thats not likely for anyone as far as I know I went to the doctor to confirm and it came out positive as well but the confusion is my doctor said it was to early from going off my app because I'm two weeks and my app says three weeks can somebody help me make this make sense