Quoted from TheLaw:Close-in-age: In Colorado, a person who is under 15 can legally consent to have sex with someone who is no more than 4 years older. Additionally, a person under 17 can legally consent to sex with a person who is no more than 10 years older.
Those laws sound much more reasonable than most statutory laws I have heard about. It always seemed ridiculous to me that a Senior in high school and a sophomore in high school that are both consenting could be committing a crime. The 4 years older part gives some reason to it.