Anywhere:

k84:In terms of law enforcement, pedophilia includes having sex with a minor. 13 years old qualifies one as a minor, and in pretty much every state in America, a 40-year-old having sex with a 13-year-old is illegal. Any questions?

You are correct within the specific qualification you added: "in terms of law enforcement."

She's not, actually. An adult having sex with a minor is illegal (given certain qualifiers), but it is not, in and of itself, legally described as "pedophilia".

Not according to Wikipedia

I quote their article:

"In law enforcement, the term "pedophile" is generally used to describe those accused or convicted of the sexual abuse of a minor (including both prepubescent children and adolescent minors below the local age of consent"

In support of that statement it cites this reference:

Ames MA, Houston DA (August 1990). "Legal, social, and biological definitions of pedophilia". Arch Sex Behav 19 (4): 333–42.