Howie Day’s too excited to be nervous about opening for Tori Amos’ two-month North American tour, which began Nov. 7 at the Tampa Bay Performing Arts Center in Tampa.

Though he’s on a much bigger stage, the 21-year-old singer-songwriter from Maine is an old pro at live performances. He has been winning over audiences since scoring his first gig at age 15: in the lounge bar of his parents’ Captain Nick’s lobster restaurant near the Bangor airport.

“It wasn’t a venue by any means,” the Boston-based Day said, with a laugh. “It’s just a little lounge attached to the restaurant where people can have a drink while they’re waiting for their table.

“From there, it branched out. Other restaurant owners, other bar owners came to our restaurant and would hear me play and then they’d book me to play their places. You can’t solicit yourself by demo tapes to get a gig in Maine. That doesn’t usually work; it’s a word-of-mouth thing, and that’s the way it’s been my whole career, everything’s been word of mouth.”

By 1999, Day independently recorded the album, “Australia,” on a shoestring budget and limited studio time, with producer Mike Denneen (Aimee Mann, Letters to Cleo, Guster) behind the boards.

After high school graduation, he hit the road, playing nearly 300 shows in a year. That work ethic paid off: “Australia” sold nearly 30,000 copies through Day’s Web site, and he won a pair of Boston Music Awards, including one this year for best male singer-songwriter.

All that caught the attention of Epic Records, which signed Day and re-released “Australia” in early June. Since then, his video for the first single, “Ghost,” has gotten airtime on MTV, and he was featured on the Jeep World Outside Festival tour with Sheryl Crow, Train, Ziggy Marley and O.A.R.

Day says he prefers the slow career build he has had to the overnight stardom of Avril Lavigne, a 17-year-old rocker who recently had two singles in the Top 10 on Billboard’s pop chart.

“That stuff’s just too much,” he said. “And how about that ‘American Idol’ winner? She went from zero to hero overnight. She must be going crazy. Right now, I’m barely hanging on with all the attention I’m getting, so I can’t imagine what she’s going through.”

Touring alone can be overwhelming, he says, but he’s enjoying every minute of it.

“It becomes a routine, a way of life,” he said. “You’re always thinking about time, like ‘What do I want to do?’ versus ‘How much sleep do I want to get?’ That seems to be the tradeoff every day. You’re always fighting to go to sleep. ‘Do I want to go to lunch tomorrow, or do I just want to do McDonald’s drive-thru and get an extra hour of sleep?’ ”

Most gratifying of all for Day is that he has done it on his terms and has gotten people to overlook his age.

“There’s a certain thing about being young and being a performer, I guess people are turned off by that,” he said. “You have to prove yourself a little bit more. It’s the typical, ‘Kid, you don’t know shit about shit, so you couldn’t possibly write a song that I could relate to.’

“This is my job, though I don’t look at it as a job. I enjoy it every night, connecting with different people. It’s new and refreshing, to an extent, every night. I’m having the time of my life.”

ON THE WEB: www.howieday.com.