There seems to be some confusion about the Age of Consent.
In the United States, it varies from state to state, within the range between 16-18 years of age. In federal law, the age of consent is 16. 16-17 is the most common age range, but a number of states, particularly in the western US have the age at 18.
In most cases, these ages of consent are the age when consent can be given, regardless of the age of the partner. In most states special consideration is given to sexual activity by those of even younger ages, if the other person is within a certain age range close to the age of the underaged person. Typically, that range is 3-4 years. In other states, penalties may be reduced if the two parties are close in age, even if one is under the age of consent.
When discussing sexual interactions between young people and adults, the age of consent is an important matter, even if one believes that age to be too low. The wikipedia article below has accurate information for the various states, as well as other jurisdictions in North America. A similar wikipedia page, listed below the other one, covers the entire world, with links to individual continents. Both are very educational, and may surprise some DUers.
http://en.wikipedia.org/wiki/Ages_of_consent_in_North_America
https://en.wikipedia.org/wiki/Age_of_consent