What is a regular menstrual cycle?

I thought I had a regular menstrual cycle but now I’m double guessing.
My cycle is normally between 24 to 27 days… is this regular?
Especially when it comes to tracking ovulation.
Can I assume I would ovulate around day 14 or is my cycle not regular enough?
Do woman get there period every 27/28 etc etc days to the hour, or does it fluctuate but still stay ‘regular’
Sorry if this seems confusing – I am right now!

Thanks