"We can't wait to start our life together," the Nickelback frontman tells PEOPLE

It’s been three weeks since Avril Lavigne and Chad Kroeger wowed the world with the happy news of their surprise engagement. But one person who isn’t paying attention to everyone else’s reaction is the Nickelback rocker himself.

“I try not to take too much interest in the world’s opinion of our relationship,” Kroeger, 37, tells PEOPLE. “I just know the both of us are very happy.”

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Lavigne, 27, and Kroeger met earlier this year while collaborating on music for her forthcoming album. Their professional relationship took a turn this summer when they started dating on July 1 – which happens to be a special day for both Canadian megastars.

“We think it’s very cool that our anniversary will always be on Canada Day,” Kroeger says. “We can’t wait to start our life together.”

Before they walk down the aisle, Kroeger, whose band has sold more than 50 million records, will hit the road this month for a European tour with Daughtry. And he’s hoping to have his bride-to-be by his side for some of those dates.

“She’ll come over and spend some time [with me] when she’s got time,” says Kroeger, who adds that they’re working on balancing their music careers with impending married life. “They’re going to throw a lot of stuff on her plate with the new record.”