Setting the rules! In a new post Christie Brinkley shared to Instagram, she opened up about being a trendsetter in the fashion industry when she rocked a risqué swimsuit on the cover of Cosmopolitan magazine in 1977.

“This bathing suit caused a stir!” the supermodel said alongside a pic of herself in a purple high-waisted bikini. “At the time all the bikinis were low slung on the hip. This high leg cut made the hip a new erogenous zone. I couldn’t figure out how to put it on as just one string holds it all together!”

“Francesco Scavullo shot all the covers for #cosmopolitan back then. He had a big umbrella with a string that ran from the middle of the umbrella which contained a light to the tip of your nose. You were in perfect light at the end of that string. They did not have retouching back then so they really perfected the make up and every strand of hair,” she continued.

Even though Christie was doing something brave by rocking that swimsuit, she admitted she felt a little insecure about bearing so much skin.

“I remember I was worried that I looked fat. I’m so glad that today our industry appreciates all shapes and sizes so we can just focus on being healthy. Not cookie cutter,” she said in the caption. “Still there is something in some young girls that often makes them feel they just don’t measure up. I was one of them. I look back at these and think that worry was such a waste of time. If only the perspective we gain with age that alleviates the worries, could be passed on and absorbed by the younger generation. But I do think shifting the focus to feeling great is a giant step in the right direction.”

Christie Brinkley

With so much life experience, Christie tries to prepare her three kids — Alexa Ray Joel, 34, Jack Brinkley Cook, 24, and Sailor Brinkley Cook, 21 — for anything that could come there way. In a previous interview with Closer Weekly, Sailor remembered what her mom told her about being confident.

“She’s mostly just told me to smile — that’s like her No. 1 advice, especially for confidence — to, you know, ‘smile and you’ll feel it,'” she said. “I honestly believe that too.”