Kellie Pickler Engaged to Kyle Jacobs

via People

For Kellie Pickler, June 15 has long been "sad and hard for me," as it is the birthday of her late grandmother, Faye Pickler.

But the traditional sadness of the day turned to happiness last week, when Pickler's boyfriend, songwriter Kyle Jacobs, proposed on a Florida beach at sunset."It turned out to be the most amazing day of my life," the fifth-season American Idol star, 23, tells PEOPLE. "My whole world changed. We both feel like we got my grandmother's blessing."

Pickler considers Jacobs's proposal a moment she hardly could have imagined. "I remember saying to Kyle, 'Baby it's like I'm dreaming – but if this isn't real, I'm going to be very upset!' "

Champagne and Tears
Jacobs meticulously planned the proposal, arranging a blanket, champagne and candles to be waiting as they strolled on the beach. "Afterward, we just held each other and had the most beautiful prayer," Jacobs says. "We had a little champagne and talked and laughed and cried."

The couple met through friends about 2½ years ago, and Pickler, who was raised by her grandmother after her mother left and her father went to jail, says she learned how to have a healthy relationship from her new fiancé.

"Kyle took away all my fear of marriage and has shown me the way love is supposed to be," she says.

Thanks to Jacobs – as well as a renewed relationship with her dad, Clyde Pickler, who's been sober for a year – "I'm in the happiest place I've ever been," she says, adding that she plans to have her father walk her down the aisle.

Pickler's engagement makes her the third recent country bride-to-be, joining pals Miranda Lambert and Carrie Underwood.

"We're all just happy for each other," Pickler says. "I'm sure we'll be having some girl talk and we'll share ideas. We just keep joking about how there must be something in the water!"