Ovulation help!

I should know the answer to this because I have 2 children already..but we are trying for our third and final and hoping for a boy (we have 2 daughters already!) We are following the old wives tale to TTC as close to ovulation as possible for make sperm to have a better chance..Therefore my question is, if I had EWCM yesterday..when would I be due to ovulate? My app says 2 days but I thought once my CM changed, ovulation would be about 12 hours later..

Any insight would be helpful, TIA!!

Pic of my precious babies ❤️