late periods

is it healthy to have periods that keep starting late??

when i was regular, my periods would start around the 18th. a few months back. it started at the 26, then 1st, and now it’s 2 days late.

is this normal? i’m 19 years old and it’s kind of worrying and confusing to see my once regular period fluctuate lol

i know i’m not pregnant since i’m a virgin

thank you!