ANDY'S ANSWER:  Normally, you can expect to get your first period about 2 years after your breasts start to develop. So I think you probably can expect your first period to happen between age 12 and 13 if your breasts have started growing. Sweating more that usual is normal, but a yellow discharge probably should be checked out by a doctor. The discharge you get before you start your period should be a clear-white fluid with very little odour. This discharge is also something that starts between 2 years and 6 months before your first period.