They're legally adults, however they don't know the difference between getting an engineering degree from Georgia Tech (best lifetime earning to cost ratio in the country for Georgia residents, equal ratio for out of state students as Harvard) and an English degree from Notre Dame.
Additionally, you don't get the "judgement" part of your brain until after you're partially through/done with college: http://www.hhs.gov/opa/familylife/tech_assistance/etraining/...