Hello, I am 15.4 yrs. old and have not started my period. I am a little over 5.6" and weigh about 125 lbs. My mom thinks I should start my period any time since my complexion has started to change (I'm started getting acne). Everyone says that I am really late at starting, but I don't eat red meat, drink non-fat or Silk milk and eat pretty healthy. I have noticed I have started eating more lately though. Are these all signs that I am going to start my menstrual period soon? When I do, should I loose the baby fat (face get thinner and extra fat around middle that I can't exercise off) - will the weight now come off easier? Will I also get taller even though I am starting so late? Thank you so much!
Yes, you are on the late side, but you are still within a normal development range. Think of it as someone has to balance out all the early developers and you happened to be picked for the role.
Girls can begin their menstrual period at one of two points -- either before their growth spurt or afterwards. This is why Dr. Tanner's stages focus on two aspects -- the shape of a girl's breasts and the pubic hair. You can read about the Tanner stages here. Your growth spurt comes in Stage 3. Menstruation begins either at the beginning of stage three or in stage four. To estimate what stage of development you are in, see the Tanner Stage Calculator for Girls .
Since you mention that you have "baby fat" that exercise doesn't effect, then I would assume you haven't hit your growth spurt yet. Then the most probable thing is that you will grow rapidly for about six months and towards the end of that growth have your first period. Since the growth needs fat to fuel the changes, the baby fat will fade.
There are several things you need to seriously consider because of your diet. Once you do begin menstruation, you need to make sure you get an adequate source of iron in your diet. Though the blood lost in menstruation is relatively little, it is still a regular loss that needs to be replaced.
Second, it has been shown in a number of studies that women with little body fat have trouble having regular periods. This is not good for the female body. Lack of periods is linked to loss of calcium in the bones. It will cause problems later in life. So while being fat is unhealthy, it is also unhealthy for a woman to be too skinny. In order to have regular periods, you need about 15% body fat.
If you are well into stage four or have reached stage five and not had a period, I would suggest visiting your gynecologist for a check-up, just to make sure that everything is all right.