PHOENIX — Gov. Janet Napolitano is giving a chilly reception to a proposal to let those younger than 21 drink — no matter what her personal experience.

 Napolitano said Wednesday she has not studied the proposal by several dozen college presidents to scrap state laws that raised the drinking age more than two decades ago to 21. Their argument, dubbed the Amethyst Initiative, is that students are less likely to engage in binge drinking and risky behavior if they are in public places like bars rather than in dorm rooms or off campus.

 Napolitano said that doesn’t make a lot of sense to her. “I gotta say I’m skeptical because we know the science of brain development even at that age,’’ she said. “And we have a real problem with young drivers drinking and driving and making a real push in our state about that.’’

 The governor credited a crackdown on drinking and driving for at least part of the reduction in fatal accidents in Arizona. “If they want to send me some information, I’ll review it,’’ she continued. “But my initial reaction is one of deep skepticism.

 Napolitano also said that waiting until 21 is not a hardship. She pointed out she went to college at Santa Clara University in California, a state that has set the drinking age at 21 since the end of Prohibition. “I didn’t drink before the legal age,’’ she said. Never? “You know what? I’m sure I did,’’ the governor responded “But that’s a lot different than changing the legal standard for everyone,’’ Napolitano said. And she said lowering the legal drinking age “probably then pushes down the age to 16 or 15 when kids start drinking. There is an effect there that happens.’’

 Arizona’s drinking age had been 21 until lawmakers approved lowering it in 1972 to 19. It remained there until 1984 when then Gov. Bruce Babbitt signed a new law restoring the previous standard.

 Much of that impetus for that change came amid threats by the federal government to cut off aid to any state which allowed drinking younger than 21.

 Napolitano confession Wednesday of her pre-21 drinking actually is the second time she has publicly admitted to a bit of youthful lawbreaking.

 In 2002, as state attorney general, she appeared with federal drug czar John Walters in an event urging voters here to reject an initiative which would have decriminalized the possession of less than two ounces of marijuana. Walters, whose official title was head of the Office of National Drug Control Policy the campaign “expects the people of Arizona to be stupid.’’

 Walters conceded that many adults who grew up in the 60s and 70s used marijuana and now lead productive lives. Napolitano, sitting next to him, conceded that list includes her. “I experimented in college a little bit and regret doing it,’’ she said at the time. “When you’re in college you do a lot of dumb stuff.’’

 Walters said, though, what was available then is far different than what’s being sold on the street today. “This is not your father’s marijuana,’’ he said. “It is more powerful and young people are using it at younger and younger ages.’’