How long does it take for periods to regularize? I've had mine for over three years and the cycle lengths still vary a ton (up to a 23 day difference)

Irergular periods. Irregular periods are one of the most common problems obgyns treat. If this is one time problem it usually resolves on its own. If this is a recurring problem you should be evaluated. There are many options available to help regulate the menstrual cycle. Schedule a visit.