The fashion designer tells PEOPLE that the gold medalist was doubtful she could wear a ball gown for her big day, until Lahav convinced her otherwise:  “I love that we could surprise her”

PHOTO: SIMONE BILES WEDDING CREDIT STANLEY BABB/STANLO PHOTOGRAPHY

Simone Biles didn’t think she could pull off her wedding ceremony dress choice, but designer Galia Lahav convinced her “absolute dream” client otherwise!

“Simone came in thinking she knows exactly what she wants and what she doesn’t fit-wise,” Lahav tells PEOPLE in an exclusive interview. “And she ended up surprising herself when she tried on a princess gown with a fitted corset top. I explained to her that also shorter girls can go with a princess gown — the trick is to add a high slit!”

Lahav adds, “This gives the gown the perfect proportions, overall lengthens the body and shows off her legs! It was such a great solution to give her variety with her looks!”

After tying the knot during an intimate courthouse wedding in April, Biles and NFL football player Jonathan Owens, 27, said “I do” again during a second ceremony in Cabo San Lucas on Saturday.

“I actually felt so sick the entire day, and when it was almost time to walk, my heart was beating out of my chest. I’ve never been so nervous before in my life,” confessed Biles, 26, while sharing details of the 144-guest affair with Vogue.

“I was nervous about having a ball gown because I’m so petite—but it works perfect,” Simone told the high fashion outlet. “The leg slit was very crucial. It was to add, in my head, more length to my body. I think this is exactly how brides are supposed to feel: luxurious, beautiful, kind of on top of the world.”

SIMONE BILES WEDDING CREDIT STANLEY BABB/STANLO PHOTOGRAPHY

Lahav says Biles wound up with four dresses in the end for the celebrations because she simply “fell in love” with all the designs after first saying yes to two dresses, “our GIMAYA and MAYA gowns,” but then discovered more while coming back to try them on.’

Biles also wore two pairs of shoes from Lahav’s collection. “Astrid Silver for the welcome party and Astrid white when she switched into the MAYA gown after the ceremony.”

As for working with the gymnast, Lahav says it was an “absolute dream come true.”

“She was SO sweet & charming!” she says. “She really lights up the room when she walks in and it was so special to share the moments of her final fitting with her! The whole process was just fun & easy going, she really put so much trust in us and I am so grateful for that. I truly wish her a lifetime of happiness, endless success & love for the future!”

Biles kicked off her Cabo San Lucas wedding celebrations at her rehearsal in a Galia Lahav JILL mini. The flirty mini dress had spaghetti straps, an asymmetrical hemline and beaded fringe, which made it the perfect dress for dancing.

For her wedding ceremony on Saturday, she wore the custom Galia Lahav GIMAYA dress. “Adding the slit really helps with showing off the body a little more and with walking, it just makes the dress lighter and gives it some flowiness,” says Lahav.

Then, for the reception, the body-hugging custom MAYA dress featured sheer panels to bring a little more sexiness to her evening. She wrapped up her night with a party dress fit for dancing. She wore Lahav’s custom G-502 that was covered in sparkles and caught the light with every move.

SIMONE BILES WEDDING CREDIT STANLEY BABB/STANLO PHOTOGRAPHY

Lahav adds that collaborating with Biles was incredibly special.

“She really was just sweet, kind and so very appreciative of working with us as were we to be working with her!” Lahav shares. “She came in prepared, knowing what she wanted and I love that we could surprise her and show her that in the end, everything is possible — even something she thought couldn’t work for her!