Opk experts please help a sister out!

So, today I'm on cycle day 18. I've been testing for ovulation since cycle day 8 because I really don't know when I ovulate. I don't track my bbt and I get no ovulation cramps so I didn't want to miss it in case I was one of those ladies who ovulated early. For the past 2 days the lines are obviously there compared to cycle day 8. I know the lines must be darker but does this mean I'm close to ovulation? Someone please explain and enlighten me. Any ladies ovulate late like me?