I need ur help

Noochie
Okay. So the Glow <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">Nurture</a> app says im 7 weeks exactly today. Making my due date January 15, 2018. But last week i had another app do the math for me and it said January 25, 2018. And just now when i was doing some calculations i got that im due January 19, 2018. I dont have my first prenatal visit until next week, but im really confused. I want to have the right date entered in on the <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a> so i can keep up with the news. Please help me figure this out. It's starting to irk my soul lol. My LMP was April 15-19.