my friend's daughter, who is also in class 8, just now had her first periods. in fact, she had taken her daughter to the doc for a checkup and the doc had mentioned this is absolutely normal. some children get their periods early, as early as age 9 or 10, while others may get it by the age of 13 and this too is normal. if you are still concerned, i would suggest you speak to the doc about it to know if your daughter needs a checkup.