Understanding the peak window

I never realized how much science goes into baby making. My first was not planned and happened, well I guess the first time. She is now 9 and my DH and I are trying for our first together.
​I'm trying to understand my body better in the process since we are now on month 3 of TTC. I've noticed that the peak for glow and most sites are the two days preceding O. Wouldn't the day you O be the highest since the sperm doesn't have as far to go to meet the egg? Any days prior to that I would think are sperm stocking days? Is it because the cervix is most open during this time and CM is the best? Maybe I've just answered my own question...
​Thanks for the feedback!