My period is late...again?

So, I got my first period a little less than a year 1/2 ago. I am now currently 15. My period started out a little irregular, which is expected. Then I got one 2x in one month, then they would come later and later. Finally, I learned I had an ovarian cyst, and once it painfully burst from being so large, my period were normal for about two cycles. Then, my next one was late. Now, I am 10 days late again, and I am wondering if this has to do with cysts. I had to go to an obgyn and one of the nurses said that there is a condition with late periods and cysts, and I was wondering if this could be possible and if anyone knows what this is. My mom is already stressed enough abut things, and I don't want to add this right now, until I need to tell her. Any help? Please? Thank you :)