Idk what to title this🤣

This is random but is it normal for periods to move each month? My periods just started regulating after years of being crazy and I’m on my third month of having a regular period, but in November it came the last week of the month into the first week of December and I didn’t get another period until January. In January it started the 10th and this month it started today? So far the app has been accurate of when I’m going to start it’s just weird that my periods aren’t coming the same time every month.