Ovulating.....Glow never has it right

Does anyone else just not know when they are going to ovulate each month. I feel like each month mine is at a different time in my cycle. Glow tells me it’s this week and all the body signs add up to it. (Besides ovulation tests I haven’t taken those yet. ) but then I get sharp pains a week later that are a sign for ovulating and my period is then over a week late then what glow predicted. I know I have a long cycle and I have changed that in glow but it doesn’t do anything it still predicts all the dates wrong. Some months I feel like they have it right other months it is all wrong. I struggling to track it and make sure we have our best chances to get pregnant cause I never know what is going to happen with my body.