[quote]Why is it illeigial {sic} to date a girl younger than you if you're 18?[/quote] It's not. It's only illegal to have sex with someone under the age of 18* - dating does not require sexual intercourse, merely going out and spending time with someone is not illegal unless the older person were in a position of authority like the younger person's school teacher - in which case it would be considered grooming and an abuse of position. * the [url=https://en.wikipedia.org/wiki/Ages_of_consent_in_the_United_States]age of consent[/url] varies from state to state between 16 and 18. Some states also have a 'close-in-age exemption'.