The first question of course would be "why?" Menstruation follows a period of approximately 14 days after ovulation. The the simplest explanation of a delayed period (with the exception of pregnancy) is the delay or absence of ovulation. Thus an obvious next question is what causes the ovulation to get delayed? The reason may be a hormonal imbalance (as in Polycystic ovaries), a fault in the system that stimulates the ovaries or failure of ovaries due to a very low reserve of eggs.
The next important issue is about the implications of infrequent or absent ovulation. Irregular ovulation will certainly lead to a delay in conception. Another impact would be on the lining of the Uterus - the endometrium which can become thick and unhealthy leading to irregular, heavy and prolonged bleeding. Women who have infrequent periods for a long time are also at risk of cancer of the endometrium. The stoppage of periods that occurs with the failure of ovaries leads to menopause. If this event happens prematurely this can affect the strength of the bones and lead to osteoporosis.
In short, it is not okay to not have regular periods. Visit a doctor and if you are trying to conceive, see a reproductive endocrinologist or infertility specialist. The doctor can diagnose the reason for irregular cycles and advice on whether the couple need to undergo any treatment. The common advice given to ladies who are overweight and have Polycystic ovary disease will also be advised to lose weight through diet AND exercise.
The bottom-line is that THERE IS ALWAYS A WAY!