The former model, 51, makes her debut on the Bravo show Tuesday, which will see her have a confrontation with Faye Resnick.
"It was a long time coming," Edwards tells PEOPLE.
The feud dates back to the early 1990s, when Edwards and her then-husband Marcus Allen were friends with O.J. Simpson and Nicole Brown Simpson. In 1994 after Nicole's murder, Resnick, 58, published a book claiming Edwards' then-husband Allen had an affair with Nicole while he was engaged to Edwards – claims both Edwards and the former NFL star have denied.
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Edwards says Resnick's book, Nicole Brown Simpson: The Private Diary of a Life Interrupted, was published without Resnick reaching out to her about its claims.
"She never met me. She didn't know me. That always bothered me, that she acted like she did," says Edwards. "I waited a long time. I'm one of those people who can wait for a lifetime to say what I have to say to somebody. It was good. I was happy to get it off my chest."
Ahead of joining RHOBH, Edwards says she was unsure what her relationship with Kyle Richards would be like, as the star is close friends with Resnick – but Edwards and Richards have become close.
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"She's a great girl and my husband [former NFL star Donnie Edwards] and her husband [Mauricio Umansky] hit it off, and so it's a nice little friendship there," says Edwards. "I think Kyle is going to let Faye and I figure it out on our own. [The book] was before she was friends with Faye. It is what it is."
As for some of her other RHOBH favorites, Edwards says she hit it off with Lisa Vanderpump and Erika Girardi, though she admits it wasn't smooth sailing with everyone (as will be revealed on the show).
"I think I have a thick skin naturally. I was a model for years and years," says Edwards. "I developed a thick skin in that business. I always said, 'I'm not for everyone. Not everyone is going to pick me and like me and I'm fine with it.' I feel the same way with friendships. I'm not for everyone and everyone's not for me.
The Real Housewives of Beverly Hills airs Tuesdays (9 p.m. EST) on Bravo.