Nick Lachey and Vanessa Minnillo
hasn't chosen her wedding cake and isn't dishing on the kind of dress she wants. But she is sure about one thing ahead of her marriage
to Nick Lachey
"The best part is that you know someone has your back, no matter what," Minnillo, 30, told PEOPLE at a youth-mentoring event in Silver Spring, Md., recently. "It's not that I didn't know that before – I kind of teetered on it – but now I know for sure that no matter what, this guy's got my back."
She added: "There's nothing we can't work out, and there's nothing we can't talk through. There's no obstacle we can't overcome, and that's a beautiful, comforting thought."
Not wanting to tip off Lachey, 37, about her bridal look, Minnillo demurred when asked about her gown. But when it comes to the cake, she admitted she loves "all flavors" and "might have to do different layers and different flavors."
And will her beloved Yorkiepoo, Wookie, be the ring bearer? "If he is, it's going to take a lot of training and discipline, because right now he's just too shy," she said. "He'd panic down the aisle and probably run off with the rings. Maybe I should get started on that, right?"
Minnillo was joined by actresses Kerry Washington, Tracee Ellis Ross and comedian Ali Wentworth at the mentoring event, part of First Lady Michelle Obama's celebration of Women's History Month. She urged the students at Springbrook High School to find their gifts and talents, and also opened up about her insecurities when she in high school.
"My lips – I see beautiful lips now – but people made fun of me for that," she said. "They made fun of me for the color of my skin … I didn't have perfect hair; I never had good shoes."
"When I was your age, I was at the most critical point in my life. I was miserable. I was internally a very sad, sad girl. I was on the cheerleading squad, and I was the president of my class. I cried myself to sleep every night."
Minnillo turned herself around by embracing her diversity as her strength, ultimately becoming Miss Teen USA at age 17. "You were all born with a unique gift that nobody else has," Minnillo said. "And that's what makes you beautiful."