My sister is almost 14, got period last year once but it hasnt happened again but she seems to get signs of ovulation like discharge. but no period?

It happens: Women will often not release eggs when cycles starts. Egg release is an important part of pacing the cycle since it forms a secondary hormone source that brings on menses if conception does not occur. They can have irregular cycles, go months between cycles, etc. After a year or so egg release usually starts & cycles become predictable. If more than 90 days have past she may want to visit her doc.