My periods are weird sometimes

My periods are weird sometimes I skip months and sometimes I start unexpectly is that normal

Yes, that is completely normal. Usually teenagers go through this, and after a few years your period will start to get more regular.
Irregularity happens because your body is just getting used to all the changes and stuff. So this can happen for a few years after you get your period. I actually deal with this as well, even though I got my period three years ago on my 13th birthday, and still it skips months and comes at the most annoying times.
However, if you are not in your teens or twenties, I would think that irregularity isn't as normal, but it still could happen. For example, if you don't eat enough (to the point of anorexia) you may miss your period for an extended amount of time until you begin to eat healthy again.
But other than that, yes it is very normal to be irregular.
Most teenagers are. I would just say to always keep a pad or tampon in your purse just in case...because if you're like me, periods strike at the worst times...