Regular periods but think depo may still be in system and TTC.

Savannah • 19 soon to be 20 and Looking forward to wonderful motherhood :)
I was on depo since I was 17 and at 19 decided to switch my birth control to the pill ,partly because the lining of my uterus was thinning and also because I wanted a less permanent option,   I am now about to be 20 on the 25th and I ditched my pill this month TTC and my periods have been regular but my cervical mucus is white and crumbly and I should start being fertile within the next few days according to my period tracking apps.  I really don't think I'm fertile yet and the depo is still in my system.  Does anyone have any advice or have had the same experience.