Hi,
I am 14 I will be 15 years old in January and I still haven't started my period.
I am kind of worried is this normal. Could it be because I do martial arts I will start it at a later age then the avarage.
Please can you help me. Thanks.

Don't worry. It's completely normal to not start your period at fourteen. Every body starts at different times, because it's in our genes. I didn't start till I was sixteen, so don't worry. It will come, so enjoy not having it while u can!