Positive OPK do I have to BD today?

Me • TTC since Feb 2017
It's my first month using opks. I had only one line yesterday and a faint second the day before. I just took a test and I think it's a positive from what's on the packaging. I'm not sure if I'll be able to BD today. Glow shows today as my most fertile and said today is the most important for BD. Do I have to today or will I still have a chance tomorrow?