How far along am i really

3👼🌈💖2018🌈💙2020💖2021💙2023 • God's timing is perfect🙏⛪
I went to the doctors on 12-08-16 n was told I'm 9w 3d so am I 13 weeks today 01-02-17 which makes it my sec trimester? Because this app is saying I'm only 12w 5days. But it doesn't add up to my ultrasound pic plz help I'm going crazy lol