It will probably be much easier to talk about this with your mother, who most certainly has been having periods for some years. Speaking to your mother when you get your first period means that she will be able to answer any questions you have, and make sure you have the sanitary products that you need. If you don't feel comfortable talking face-to-face at first, you could send a text or Whatsapp message, until you feel ready to talk more openly. Having periods is a sign of good health and shows that you are developing normally. It's good news, even for your parents.
At what age should I tell my parents that I got my period?