Early Ovulation

Cheyenne

How common is it to ovulate early?

I have a 30 day cycle. My Predicted ovulation is on the 18th but swear I could have ovulated on the 14th or 15th by going off of my CM. That would have been day 13 & 14 of my cycle. Today CM is not heavy like it was the last 2 days.

On the 14th (day 13 of cycle) I had a tiny bit of spotting. Which I assumed was just ovulation spotting.

Any idea? Or input? Thank you in advance!