Is it normal to be late?

Period: I assume that you are referring to your period being late. Many women, particularly young women have occasional irregular periods - a few days late, a few days early, heavier or lighter than usual. Sometimes stress, fatigue, or inadequate sleep can be a factor. If you are sexually active and had unprotected sex, then you should take a pregnancy test.

Periods might be a: little irregular. Reasons for missed/late periods: low body weight, obesity, marked weight ^ or v, over-exercise, endurance athletics, breast-feeding, ^ stress, illness, eating disorders (bulimia or anorexia), anovulatory cycle (no egg released), travel, hormone irregularities, drug use, meds (i.e., birth control) or medical problems (i.e. PCOS). #1 reason is pregnancy.

How often?: People are normally late from time to time. Things come up they can't anticipate - traffic, an important phone call, etc. If people are consistently late this may speak to an underlying issue - difficulty with being reliable to other people, trouble with planning and impulse control, difficulty saying "no" (e.g. getting off the phone from a non-urgent call to be on time), obsessing, etc.

Late for What?: If you mean your period no. Do a pregnancy test to see if you are pregnant.