SACRAMENTO (CBS13) – An unbelievable milestone for the once-conjoined twins: they’re now three-years-old.

“Happy Birthday Eva and Erika,” a crowd of family and friends sang to the twins Saturday.

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It was an emotional day for both mom Aida and dad Arturo.

“It’s a big deal for both of us,” Aida Sandoval said.

It’s a celebration everyone dreamed about, but didn’t know would happen.

“Being at the hospital, I can’t picture anything but getting the girls healthy,” she said.

Erika and Eva Sandoval were born conjoined at the chest and at 2-years-old underwent a risky surgery to separate. After 17 hours, with a team of 50 doctors at Lucile Packard Children’s Hospital in Stanford, they were successfully separated.

“To know that they were going to have separate individual lives, it was such an amazing prayer that was answered,” said the girls’ at home nurse.

After separation then began the true recovery.

“It was a lot of unknowns and we didn’t know how to do things for them and it was a lot of different things. How do we put a diaper on them? How do you hold them? How do we change them?” said Erica Keesis-Segura, who was with the twins in the NICU in Stanford. She also drove up for the party.

With plenty of help and time to heal, the girls are now thriving.

“They are missing one leg, but they are normal. As normal as they can be. To us, they are perfect,” Aida said.

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They’re also exceeding all expectations.

“They said they would never be able to sit down, they were still in the hospital when they sat,” Arturo said.

They’re even taking their separation in stride.

“The amazing moments are those moments when they start to get up on the couch, when they get up on the little horsey they just got. It’s the little things,” Aida said.

From little to now big leaps in life.

“We are excited, we are going to start preschool sometime soon, hopefully this year,” Aida said. “It’s nerve-racking. I know I’m going to cry, but I know it’s the best thing for them.”

They’ll still be working on strengthening and getting new wheels, but dad says nothing will stop them.

“So you don’t have your leg, that’s not a big deal, that’s not a crutch, it’s just a thing you have to live with,” he said.

Plus, they always have one another.

“I actually cry when I see them hugging each other,” Aida said.

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And by the looks of their picture perfect third birthday, there are only tears of joy.