Early fertile window

Mi
I have already posted about first time using opk. I ordered them from internet and now I wait. 
​My question is: I'm on CD 8 and my cervix is soft and high. My CM is wet and slippery. 
​Also, I started bbt first month so I can't count on it.
​Is it possible that I start my fertile window earlier than I thought?
​P.s. My cycles are now 26 days because I take progesterone from 15 CD till 24 CD
Thank you for your help!