first time with ovulation test

This is my first month using OPKs and I am a little confused. Glow predicts I am ovulating on Thursday (3/23). I took my first opk on 3/18 (pictured). So far none of these look positive, but the rest line is actually getting lighter. Does this mean I already ovulated? Perhaps between the 3/18 and 3/19 tests?? Also, CM started to become egg white yesterday (3/19).  Thanks.