I haven't taken birth control pills in forever so I'm in need of a little advice.

My period usually comes around the 20th-26th which would give me time to start my pills that following month on the first Sunday but lately my period has been lasting from the 28th-3rd which so happens to potentially get in the way of me starting my pills on the first Sunday of February while being on my period.

I have always had the mentality where I wasn't supposed to start them if I'm on my period am I right or wrong?