TTC #1

Hey! I'm 24 and TTC. On 6th month of trying...I havnt been tracking or counting just a lot of BD! So, I install the app and I'm counting dates etc! I've been seeing post about pre-seed...definitely going to try it!! But my question is...could Glow have my ovulation days wrong? I counted and I think they should be April 19-24 but Glow has April 16-22. Is it anyway to get an exact day of ovulation? I'm really trying my hardest 😟