The thing is that you can't and shouldn't just try and guess that you have it. You should be diagnosed by a rhuematologist as that falls under his specialty. Fibro is painful, something as simply laying in bed or getting hugged by your boyfriend/husband hurts and that hurt lasts for a period of time, even up to 5-10 minutes after being touched. There are also a lot of other issues that go along with it. There are 18 pressure points on the body, you have to have pain in 11 of those areas to qualify for a diagnosis of Fibromyalgia. A lot of patients say this problem gets worse over time and many have a hard time just walking. There is a form of Fibro that does affect children and teens as well, but it is less common.
It is definitely still possible that you have it. Just because most don't get it until they are 30ish, doesn't mean that you can't get it at a younger age. There is also Juvenile Primary Fibromyalgia Syndrome (JPFS) which occurs in children.