Is this even possible?

My period used to be super irregular. Like I'd go months without it. I took birth control which fixed it--until I came off birth control to try for a baby. My cycles went wild all over again、 going from 35 to 105 days. Over the last year they've evened out to every 35-39 days (for 10 months straight they were like that) but last month I ovulated a week early and my cycle was only 30 days! This month I ovulated early again and I'm just wondering if it's normal for your body to make its cycle shorter and shorter