I’ve got brown stains in my pants, it’s not my period and not painful, what can it be?

Hi girl of 10,

You have probably just entered puberty, and what you are experiencing is totally normal. Girls start puberty at different ages, and the way puberty develops varies from person to person. Puberty starts when sex hormones start to be produced, and this happens for most girls when they are between about 10–12 years old. Puberty starts in small ways and there are big differences in how fast puberty develops, and how the changes occur. The first sign is often that the breasts get a bit tender, and that the nipples change shape and size. There are big differences in how this takes place from girl to girl, and everything is quite normal.

You can read more about it in this article: A Short Boob Guide for Girls

It is normal to have a discharge a long time before your period starts. This discharge is a kind of slime from the glands in the vagina and uterus, it is clear or whitish, and it has no smell. The brown stain in your pants can be a sign that your period is coming soon. Menstruation is very unstable at the start and there may be a long gap until the next time you see that stain, or until your period starts properly. When it does come properly, you will see fresh, red blood in your pants. However, at the start and end of the period the amount of blood is so small that it becomes brown before it reaches the pants.

You might also like: Brown stains in my pants, can it be the period?

A lot of things happen to your body when puberty starts, and it is quite normal to have a lot of questions about this. You might learn more about this at school, or you can contact the school nurse and talk with her about everything you are wondering about. 
You can also read these two articles:

What Happens When Girls Reach Puberty?
What is the period?

Best wishes, boyandgirl.info