I need answers/ TTC

Ok I’m just wondering ladies, if I been TTC for 11 months and my cycle is 28-31 days average 28. Ok my period lasts 8 days and I keep up with ovulation but would would I really know when I ovulate if I never know how many days until my next period. But March 28 I had a period and didn’t have a period until May 8 I was 12 days late so if I had a period may 8 went off on May 15th would my ovulation date still be May 22 but this app is giving me May 25th so I don’t really know but if I ovulated on May 22 I will be 8 dpo. Should I wait a lil longer to test? My next cycle pose to start June 6.