Big month for Derek Jeter -- first he gets the Marlins and now HIS FIRST KID! 

Jeter's wife, Hannah Davis, gave birth to Bella Raine Jeter on Thursday, August 17, Jeter's media outlet The Player's Tribute confirmed. 

The Yankees tweeted a message to Jeter ... saying, "Congrats to Derek & Hannah Jeter on the birth of their daughter, Bella Raine Jeter. We can't wait to meet her!"

Question is ... with Jeter expected to buy the Marlins, will the kid grow up rooting for Miami or New York!??!

Jeter and the Sports Illustrated Swimsuit Edition cover model started dating back in 2011. They got engaged in 2015 and finally tied the knot last year in Napa, California. She's 27. He's 43. 

Bella is their first child.

Back when Jeter retired from baseball in 2014, he said he wanted to start a family. Mission accomplished. 

Congrats!