answer:Cycle regularity refers to how consistent a cycle is, how frequently it happens exactly the same way. An extremely regular cycle is one that always comes a certain number of days from your last one. A woman who always gets her period 27 days after her last one is very regular, a woman who gets it between 26–28 days after her last is less regular, a woman who gets it somewhere between 22–31 days later is very not regular (irregular?). Some women get it every 28 days and 15–18 hours, and this is very regular (but also very rare). Your cycle is, however, entirely normal. While it is true that ovulation usually happens around the 15th day, if you’re using that as a birth control method, you may want to just buy some ovulation sticks and double-check in case that’s not when you ovulate.