Even though you've had it for so long, starting it as early as you did doesn't necessarily mean you'll be regular at least for another year or two.
Also, if you've been under stress
or been ill that could be the cause.
If you're not having any pain or other problems I'd give it a little time (only if you're sure you're not pregnant). If you haven't gotten it in the next two weeks I'd talk to your mom about making a doctors appointment for you. There could be something more going on. Best of luck!