why am I excited over opks?!

So today is cycle day 5.  I already started testing since this is my first month using OPKs.  My last cycle was 10 days late.  That was my third cycle since ending BC...so I'm still trying to figure my body out. The lines are getting darker already! This is exciting! I didn't suspect ovulation issues, but do have endo, so I wanted to be sure.  Hoping to see a positive before next Sunday when my hubby goes out of town...otherwise I sure hope it waits til he gets back!