Is it normal to not get my period in over a year? & what is the cause?

Maybe & it depends . It could be normal depending on your age. It can be caused by menopause, a pituitary tumor, chronic illness, an eating disorder, psychological stress, pcos, to name a few.
Amenorrhe. If you are less than 35 years of age it is not normal, specially if you are not taking any bcp. You need to see your gyn for further evaluation.