SEATTLE — As Washington state readied to become only the second state to allow people to buy marijuana legally without a doctor’s note, lines were already forming in front of the lucky few stores that got last-minute approval to sell.

At Cannabis City, where the owner wasn’t planning to open his doors until noon Tuesday, a 65-year-old retiree named Deb Greene, showed up just before 3 p.m. Monday. She had a chair, sleeping bag, food, water and a 930-page book.

“I voted for it, and I’m just so excited to see it come to be in my lifetime,” she said. “I’m not a heavy user, I’m just proud of our state for giving this a try.”

The start of legal pot sales in Washington Tuesday marks a major step that’s been 20 months in the making. Washington and Colorado stunned much of the world by voting in November 2012 to legalize marijuana for adults over 21, and to create state-licensed systems for growing, selling and taxing the pot. Sales began in Colorado on Jan. 1.

Businesses including Cannabis City, which will be the first and, for now, only recreational marijuana shop in Seattle, got word early Monday morning from the state that they were licensed marijuana dealers.