It is totally fine to have your period at this age!
My advice would be to use PADS, not tampons, tampons would be for when you're a bit older! Pads are just a strip of soft material, which you can stick in your underwear, and that will absorb the blood that comes out, so that it doesn't leak through to your clothes or on furniture.
Make sure you take your pad out and put a new one in every few hours, to keep you fresh and smelling nice.
When you take your pad off, wrap it in some toilet paper, a plastic bag, or the wrapping the pad came in. If you are in a toilet where there is a bin next to it, put it in there, otherwise, put it in a regular bin and try not to be too obvious with it!
Keep some pads in your school bag and a bag when you are going out somewhere, so that if you need to change your pad you have one that you can use.
Periods could last anywhere from about 2-7 days. When your period is finished, it will start again in about 21-35 days. If you want and if you have a phone, iPod, iPad, tablet, or a device similar to that, you can download an app, which will help you keep track of when your period will be. You just need to fill it in when you have your period, and then the app will estimate when it will come next once your period has finished.
If you have a sore tummy or back while you are on your period, that is normal. If it gets bad you can use a heating pack to lessen the pain, or take some medicine for it, in that case tell a parent or guardian about it and they can get you something to help.
If your period comes earlier or later than you expected, that is ok. When you first get your period it is normal for it not to be regular and persistent.
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