So do you this is more accurate?

Tyra • My 2 rainbow babies Emari 04/08/17 & my son Drew 08/21/18 & my baby boy Emon 10/15/19👶🏽👶🏽💙💖

I went to a ovulation calculator online and it said I ovulate 28th-8th of December. According to glow I only ovulate 27th-4th. Which one do you thinks more accurate?