Can you change the weeks preg in nurture?

Brittney • I`m 32 years old and have a almost 2 year old son (bday 9/3) and pregnant with our little girl (due 10/4)
<a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">Nurture</a> has me at 4 weeks but i ovulated on the 18th or 19th so I'm not that far along. My line is darkening up though!!! But that does not look like a 4 week line right?