When do I ovulate?

Had lower back pains on one side and EWCM on CD25, and then got my peak the next morning CD26 (yesterday).

I know how to read a positive and negative OPK but what my question is, is do I ovulate 24-48 hours after my first positive OPK (CD25) or do I ovulate after my OPK peak (CD26) ? I’m trying to figure out if I ovulated yesterday or If I ovulate today.