I have a app that keeps up with my periods n ovulation it says i'll get pregnant if i had sex today but my period 10 days late is the app wrong

Apps: These apps just predict the day you ovulate based on the information you input. Its just an approximation and is the same thing as counting cycle days like women used to do and still do. If you're ten days late check a pregnancy now as you may already be pregnant. For better prediction use ovulation prediction kits, which are found at most of the same stores you can buy pregnancy tests