The mother and child José Fernández left behind

Last August, a newly pregnant Maria Arias sat next to her boyfriend José Fernández at a family dinner, preparing to learn whether they would have a boy or a girl.

Fernández, the Miami Marlins’ pitching ace, cut into a large layer cake, revealing the color pink: a girl.

“I knew it, I knew it,” Fernández cheered and clapped, smiling broadly.

“He was super happy it was a girl,” the 24-year-old Arias told Univision News during an exclusive interview about the late baseball player, who died in a boating accident a month after cutting the cake.

“He always wanted a girl and we thought it was a girl.”

Arias, who gave birth to Penelope in February, said Fernández was thrilled about becoming a Dad, even though the couple’s relationship was just a few weeks old when she became pregnant.

Raised by a single mother and his grandmother in Cuba, Fernández didn’t grow up with a stable father figure.

“I think he looked forward to being everything he never had,” Arias said. “His mom was his Dad … and he looked forward to being a good figure for his daughter.”

[WATCH THE DOCUMENTARY 'JDF16']

Arias had met Fernández through relatives, and the pair were distant friends for years before beginning to date in May 2016. Arias described Fernández as “kind, protective, very loving and romantic … he was just a beautiful person.”

When he came home from road trips with the team “he would always get me roses,” she remembered. “He wrote me letters, beautiful letters, written in cursive, with a penmanship that I wish I had. He was very expressive and fearless when it came to his emotions and I loved that about him.”

And yet their pregnancy, though happy, came as a surprise. “It was a shock,” said Arias, who admitted to being worried in the days after she got the results. In those moments, Fernández was a calming force, she said.

“I was super nervous, ‘Oh my God what are we going to do?’” she says. “And he was ‘don’t worry everything’s going to be ok.’”

The night of Fernández’s death, Arias, who was four months pregnant, was out with him briefly at American Social Bar on the Miami River, before heading home.

Fernández had taken his boat to the bar after the Marlins night game ended around 10:30 p.m.

That night, he shared a secret with her: “He told me that he had made a baseball glove for Penélope to play catch with her,” Arias said. “He was supposed to keep it a surprise but he couldn’t hold it anymore.”

Around 1 a.m., they said goodnight, and Fernández told Arias he would see her soon, at home, after he took the boat back to the marina.

“In my mind by the time I got home he would be there also,” she said. “When I saw that he wasn’t I started to get worried.”

She took a shower. When she got out of the shower she saw that he still hadn’t texted or called. “That’s very odd for somebody like him. We always kept in touch no matter what we were doing,” she said.

She had no idea that instead of taking the boat straight back to the marina, Fernández had taken a quick spin out to sea, something he loved to do at night.

Arias began furiously making calls – to the marina, the bar, the Coast Guard and her brother-in-law, also an avid boater. No one could locate Fernández. She told her brother-in-law, “Jose’s not here, he was out on the boat. I’m scared.”

Finally, at 6 a.m., her phone rang. It was Jose’s stepfather, Amaury Hernández. He was the one person she hadn’t called because she worried about troubling Jose’s mother. “I didn’t want to pick up the phone,” she said. She suspected it was bad news.

When he told her police had arrived at the house, she fell to the floor. “Then I knew,” she said.

She later learned that at about 3 a.m. Fernández's boat had inexplicably smashed into a rocky jetty off South Beach, killing him and two other young men.

Everything else that night “felt very robotic,” she said. “I walked because I had to walk, I talked to people because I had to talk. But I wasn’t there.”

Since Penélope was born in February, life has been bittersweet, Arias said.

Besides losing the father of her child, an investigation found Fernández was at fault for the accident and had excess alcohol in his system, as well as cocaine. Two other young men, Emilio Macias and Eduardo Rivero, died in the accident. Their families have each sued the Fernández estate for $2 million for wrongful death.

While lawyers take care of the accident issues, Arias is focused on Penélope.

Penélope is a very relaxed baby, doesn't cry much and recently accompanied her mother to the premiere of Univision's documentary about her father, 'JDF 16.'

“The only thing I can say and promise her is that I will never let the memory of her father die,” Arias said.

She vows to talk about him, show Penélope videos of the couple and of Fernández playing and pitching, and spending time with his family.

“I will talk about all the beautiful things we used to talk about and hope that in some way that will make her feel that he’s there,” she said.

For Arias, the night they cut the cake and learned they would have a girl remains one of the best memories of her relationship with Fernández.

She recalls crying and crying in the car that night, with joy. “It was a very happy moment for us. Just really nice.”

Additional reporting by David Adams