Your wisdom teeth are the molars sitting furthest back in your mouth. At a young age, it is important to determine whether there is enough room for the wisdom teeth to fit in the mouth. This can be determined using a special X-Ray called a panoramic radiograph. Given enough space, the wisdom teeth will usually appear in the late teen years.
As is often the case, there is insufficient arch length to accomodate the wisdom teeth. If left alone, they can become impacted (stuck). It is imperative that this risk is identified well before any discomfort arises, as the difficulty involved with removing the wisdom teeth increases with age, as the roots of the wisdom teeth continually grow longer, and the jawbone becomes harder.