So I've had my period for 3 years already and they still come at irregular times. The last time I had my period it was two months apart. Why are the time lapses so irregular. (no I don't have sex)

For many women, that is how they have them. You can get a complete exam to rule out any problem, and they can see about medication to regulate them. There are just countless reasons it could be this way.

Everyone is different. Hormonal changes as you age can have this type of effect. If you only have a 3 yr. history, you are what-16 yrs. Old?

Everyone is different. Hormonal changes as you age can have this type of effect. If you only have a 3 yr. history, you are what-16 yrs. Old?
I'm 15.

It's not unusual to have irregular periods in the first few years of starting as there are a great deal of hormone changes going on. Some girls will be every 28 days from the start, but many will have some cycles shorter than this and some longer, often jumping around and not very predictable. If you start to skip a few months between at this stage, it would be wise to talk to your doctor about it.

See a doctor.

See a doctor.
Why, she's 15, still way too young to automatically assume there is anything wrong as its not unusual to be irregular at that age range.

The irregularity of the period for short term is normal because of the stress, exam tension, hormonal disturbance, junk food, etc. but if it continue for years then meet your doctor once.