My 12 year old cousin thinks she is going through a growth spurt: she eats a lot, gained weight, moody, and when she gets new pants they grow out fast, also she got her period, is she?

• (Perfect age!)
• Menstruation begins, almost always after the peak growth rate in height (average age is 12.5 years).
  

Once girls start to menstruate, they usually grow about 1 or 2 more inches, reaching their final adult height by about age 14 or 15 years (younger or older depending on when puberty began).

So pretty much she is going through one, hope I helped!