WASHINGTON — In November, D.C. voters get to cast their ballots on the legalization of marijuana. And if local parents in the metro area are putting off that drug talk, experts say it’s time to start.

“Between the ages of 10 and 12, the conversation should start coming up,” says substance abuse counselor John-Mike Nelson of Virginia Counseling Services.

Wait too long and it could be too late. “At 15 and 16, they are already in high school and pot is already a very popular gateway drug,” Nelson says.

Twenty states and the District of Columbia offer medical marijuana with a doctor’s prescription. In January, Colorado became the first state to sell pot as a recreational drug; Washington soon followed.

Many parents in those states scrambled to address their children’s natural curiosities and pressures felt from peers.

According to Colorado’s Times Record Online Edition, 60,000 copies of the University of Washington’s pamphlet “A Parent’s Guide to Preventing Underage Marijuana Use” were distributed is less than six months. Even more were downloaded.

Cheryl Shuman, executive director of Moms for Marijuana, an advocacy group that emphasizes legalization and education, recommends, if legalized, parents tell their kids that marijuana is similar to alcohol or beer: one has to be a certain age to use it.

She says when talking with your kids, focus on facts over fear.

“Instead of trying to use parental scare tactics, like this is going to happen or that is going to happen