It could be around 11 though 14. But it doesn't depend on what grade you are in. Some times your school will talk about it when your close to the age of getting your period. But ask your school nurse if you want more information.
I'm a man and in 6th grade we had one teacher all day and One class for all subjects. So it's a female question 10 yrs old Was about When My daughter had her first menstrual cycle. She was in the fifth grade.so it depends on the individual. Glad my ex wife to care of these situations
There is no certain age. It really depends on a few factors: if you've started going through puberty yet, when your mum had hers, and your nutrition. The average age is 10-15 years old. It's okay if you are early, or if you are late. Ask your mum when she got hers and that will give you a reasonable estimate on when you will get yours. If all of your friends have, don't worry. This is just around the time when girls start their cycle.