In a sit-down interview with Gayle King on CBS Mornings Wednesday, Williams, 41, opened up about how she felt after her final match, her hope of giving her daughter, Olympia, a sibling and whether or not tennis is in her future.

The 23-time Grand Slam champion said she was “not very happy” the morning after she lost in the third round of the US Open in September. “It was more or less like, ‘I can’t believe I let that match go,’ more than anything,” she told King.

She had said she would be “evolving away from tennis” after the tournament in a first-person essay for Vogue, but has since said she is “not retired,” and her chances of a return are “very high.”

When King asked whether the door was still open, Williams gave a definitive “no.”

“I’ve literally given my whole life to tennis, and it’s time for me to give my life to something else,” she said.

While her dad is pushing her to get back on the court — “My dad is like, ‘Serena, you should play like, two more Grand Slams,’ and I’m like, ‘Dad, stop'” — it doesn’t seem like that’s likely to happen anytime soon.

“I feel relief when I look at the court,” she said as she and King sat alongside the court on the property of her and husband Alexis Ohanian’s farm in south Florida. “I’m so happy I don’t have to train for two hours a day.”

She said it’s harder when she looks at “old pictures,” and thinks, “‘Oh, I miss that.'”

Though she has a lot more time on her hands now, Williams said she finds it quite difficult to enjoy the downtime after so many years of a rigid schedule. “It’s so hard for me to relax,” she told King with a laugh. “I don’t know how to relax. I have to schedule it in my schedule.”

Now, Williams is focused on raising her daughter, Olympia, 5, who she told the PEOPLE Everyday Podcast is pretty happy about her mom’s new lifestyle.

“She wants to make sure that I’m aware that I should have time on my hands and I need to spend more time with her,” Williams told host Janine Rubenstein in December.

The toddler has also made it clear to Williams that she’s keen to be a big sister, as she’s noticed many other kids in school have siblings. Williams tells her that she’s “working on it.”

Having another child was a contributing factor in Williams’ decision to step away from tennis, too. King shared that she said if she were a man, “in the health she was in, she’d probably still be playing tennis because she loves it so much, but family is also a very top priority.”

Aside from focusing on expanding her and Ohanian’s family, Williams is also channeling her energy into her venture capital film, Serena Ventures. Now that she’s not winning on the court, she said “winning to me is just picking out the best deals to invest in.”

The firm focuses on funding companies with diverse backgrounds.

“We need people like me, we need women writing the checks, because I really am a big believer in like attracts like.”