Even when using opk, how do you know exactly when (and if) you ovulate?

M🌻 • TTC Baby #1 with the love of my life! ❤️

Using opk and they go low, high, peak. Peak just means there is a rise and ovulation will occur within 12-36 hours from there. Everyone is posting how many dpo they are- how do you know the exact date you ovulated and IF you even ovulated? Is there a chance women don't? Do you consider you ovulated on the day your test said peak? Thanks :)