Kelly Clarkson had never been in love – and never thought she'd be a bride. At 30, there is no question that the blunt-talking power-anthem singer – and patron saint of Miss Independents everywhere – is having a major Cinderella moment: Fresh off her triumphant performance at the presidential Inauguration, Clarkson is nominated for three Grammys at the Feb. 10 ceremony, working on two albums, prepping for a summer tour, renovating a house in Nashville, in love for the first time ever and planning a fall wedding with her fiancé, Brandon Blackstock, 36. Clarkson dishes in this week's issue of PEOPLE on how she fell for Blackstock, her wedding plans (she has a dress!), and why she can't wait to be a mom.

"I didn't know life could be this happy," Clarkson tells PEOPLE, moments after showing off her canary yellow diamond engagement ring, which Blackstock designed with Beverly Hills jeweler Johnathon Arndt. The wedding gown "is my personality in a dress," she tells PEOPLE. "It's sweetly damaged. A little rock and roll. A little tattered. Nothing like a princess thing!" In the past, notes the original American Idol star, "if somebody would've sent me 'Don't Rush'" – her loved-up new country single with Vince Gill – "I would've laughed in their face. I would've been like, 'That fairy-tale song you just sent me? I can't sing about that. It doesn't exist.'"

She says she had no interest in kissing many frogs along the way. "I've only had three other boyfriends that I dated, and not really seriously," says the Texas native, who first spotted Blackstock – a manager for country star Blake Shelton – at a rehearsal for the American Country Music awards seven years ago. "My friend and I had just gotten out of horrible relationships," she recalls. The problem? "I was dating skinny jeans and I needed Wranglers," she says. But as she soon learned, Blackstock was married at the time. (He also turned out to be the stepson of Reba McEntire, who later became her mentor and whose husband, Narvel, now manages her career. Then, at last year's Super Bowl, the pair reconnected. "He'd been divorced for a year, and it was kind of like, 'Is this too soon?' But it just worked."

Clarkson says Blackstock "is everything I ever wanted in a guy." He has even inspired her to face one of her biggest fears and take her first flying lesson recently. "The first 15 minutes I was like, 'I'm never doing this again!' I had a Vulcan death grip on this joystick-looking thing." But by the end, "I was sold," she says. "My whole thing for 2013 is to do something every month that I never thought I'd do." That includes becoming a stepmom to Blackstock's two kids with his ex-wife Melissa, with whom he shares custody: Seth, 6, and Savannah, 11. "I wasn't really into kids, but Savannah and Seth are so awesome," says Clarkson, who counts homework helper among her favorite new duties. "We're gonna wait a bit, obviously, but we'll totally have a kid."

First, though, comes the wedding, an outdoor affair that the couple are planning for early fall with 200 guests at their Nashville home. It's was there that Blackstock proposed in December. "We have this amazing downstairs basement…We always play darts and drink beer and listen to vinyl," she explains. Blackstock had intended to pop the question during a darts game, "but out of nowhere I just said, 'Thanks for being an awesome guy.' I've never been loved properly by a man, and I was just like, 'I thank you so much for that.' Then all of a sudden he leans in and kisses me and he's on his knee."

For the self-described "hopeless romantic," it's the ultimate happy ending. "I don't even know how to not be cheesy about it," she says. "I finally feel like for once, I don't have to be so independent. He's someone who looks out for me. I always wanted that in a man. It's the most exhilarating feeling. And the most safe feeling too."

*Also In This Week's 'People'*
Exclusive Book Excerpt – Shirley MacLaine's Daughter's Shocking Tell-All
Inside Ashley Judd's Split: "Their Relationship Just Ran Its Course"
Princess Kate's Out And Showing! "She Looked Healthy. Her Skin Looked Very Good"
Kelly McGillis Remembers Top Gun: "[Tom Cruise] Always Made It A Point To Be Kind And Respectful"
Josh Duhamel: "I Had Taylor Swift's 'I Knew You Were Trouble' In My Head For Three Days"

The new issue of People magazine, featuring Kelly Clarkson, is on newsstands everywhere now.