36 years old with 4 kids- since my last baby 2 years ago, my menstrual cycle is always 24-25 days. bleeding is normal and only lasts 4-5 days. is this normal? my cycles were never long but used to be 27 days before kids?

Menstrual cycle length is a function of ovulation frequency. It almost always occurs 14 days before the onset of the next menstrual period. Your cycle length has been altered by the previous pregnancies and are normal. If the amount or days of bleeding increase then see your GYN MD for that problem.

it normal if a pregnancy test is negative

A normal menstrual cycle can be as short as 21 days and as long as 35 days. Cycles often get shorter as we age.