Serena Williams is officially back. She revealed on Instagram on Wednesday that she will return to professional tennis on Thursday, at Indian Wells, which coincides with International Women's Day. 

 It would be a bit of an understatement to call Serena excited.

A lot has changed for the tennis superstar in the past year. She gave birth to her daughter and endured scary ordeal in the hospital after having an emergency C-section that left her bed-ridden for six weeks. Her return coincides with a new Nike ad campaign, unveiled during Sunday night's Oscars broadcast, with Williams spreading the message that "there's no wrong way to be a woman." 

On Thursday, Williams will get back to what thrust her into the public eye by returning to the tennis court against Zarina Diyas at Indian Wells in California, one of the larger non-Grand Slam tournaments. Williams hasn't played in a singles match since Jan. 28, 2017, when she won the Australian Open while approximately two months pregnant. After that, Williams took her leave. She gave birth to her daughter, Alexis Ohanian Jr., on Sep. 1 before suffering a serious scare post-pregnancy, in which Williams said she could have died without the quality health-care she had. After six weeks of bed rest, Williams started practicing again in December. She was hoping to be back in time for the 2018 Australian Open, but she ended up withdrawing.

Williams has played professional matches, just not singles. Her official return was on Feb. 11 in a doubles match with Venus Williams in the Fed Cup. She was visibly rusty, and the sisters were swept 6-2, 6-3 against the Netherlands.

According to Venus, however, Serena is just fine.

"She's got power, depth. She knows how to play," Venus said at the Tie Break Tens Tournament in Madison Square Garden, via ABC. "Yeah, awesome game."

Williams returns to the singles pro circuit with a clean slate. She isn't ranked officially, but she's one Grand Slam title behind Margaret Court. Court finished her career with 24 Grand Slams, whereas Williams has 23. 

Williams could face Venus as early as the third round in Indian Wells, if the sisters both advance. Serena's first opponent will be Diyas, while a potential second-round match would be against Kiki Bertens.

There's a lot on the line at Indian Wells. It will be a good first look at Williams to see where she stands, and although it's probably unrealistic to expect her to win, gauging progress will be key. Williams' goals, however, are as lofty as ever.

"Serena's target will be to win Grand Slams," said Williams' coach, Patrick Mouratoglou in an interview with "She knows that coming back might take some time, but her level of expectation is high as always. There are three Grand Slams (French Open, Wimbledon, US Open) left this season. They will be her three main goals for 2018."

Williams is a three-time French Open winner, a seven-time Wimbledon champion and a six-time US Open winner. Williams is already 36, while Court retired when she was 35. Longevity is hardly a question for her. Williams is the oldest woman to hold a WTA No. 1 ranking at 35 years, 224 days, holding the spot until May 8, 2017. To leave, miss a year, have a child, and return at age 36? That sounds like Williams' kind of challenge.