Apps are off?

Anyone else have a couple different <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">pregnancy apps</a> and this one is a day later than the rest? All my other apps say I’m 5 weeks and 6 days. This app says I’m 5 weeks and 5 days. I even did a pregnancy week calculator and went off of my last period and it said 5 weeks and 6 days. I’m so confused lol.