No period? should I get it checked out?

Devin
I don't keep track of my period. I probably should but I just don't. However, I do know that my period is pretty regular. Regular enough to know when it's coming. But it went away. I know for sure that I haven't had one since school started (August 29). Should I get it checked out? It's about to be at least 13 weeks since I've a period.