How accurate is everyone's Glow predictions when it comes to ovulation?

I've been off of my birth control for a week, and had a period directly after that only lasted three days. Today I felt as if I could have had an ovulation day but Glow predicted I wouldn't be ovulation until Saturday. I did pick up some ovulation tests today, but I was just wondering how reliable my Glow colander truly is.. I'm new to Glow and have never really tracked my ovulation before either!