Super irregular periods

Louisexxxx
I am 16 and I started my periods when I was 11. I've had a past of irregular periods e.g being on for 6 months straight. I then went back into a normal routine and last year my periods became irregular again. I was on in May 2015, then October 2015 and finally December 2015, I have not been on since. Should I go to the doctors or is this normal?