Dates unknown

Kathy • 27, first time TTC. My SO is my best friend! I couldn`t ask for someone better to take this new step in life.
A lot of people here seem to know their cycles pretty well. I'm 27 first time TTC, my flow is pretty regular(once a month) but my dates are all over the place 25 days 28 days, 22 days, does anyone else have this sort of thing? Any advice on how to track it better?