Since AoC is determined by state, it struck me as odd that there would be laws at the federal level that protected anyone under 18 when some states set there AoC to 16 or 16 so I looked and it up, and yup there really is.

{Chapter 117, 18 U.S.C. 2422(b)} forbids the use of the United States Postal Service or other interstate or foreign means of communication, such as telephone calls or use of the internet, to persuade or entice a minor (defined as under 18 throughout the chapter) to be involved in a criminal sexual act. The act has to be illegal under state or federal law to be charged with a crime under 2422(b), and can even be applied to situations where both parties reside within the same state but use an instant messenger program whose servers are located in another state.[14]

Under the Federal Laws section for anyone else curious

https://en.wikipedia.org/wiki/Ages_of_consent_in_the_United_States