Her whole family was with her. Taylor Swift’s mom, Andrea, dad, Scott, and brother, Austin, all gathered in Kansas City on Christmas Day to watch her boyfriend, Travis Kelce, and the Chiefs play. Also on hand? His dad, Ed (mom Donna was in Philadelphia watching their other son, Jason’s, game). “It’s only been five months, but there’s no doubt Taylor and Travis are super serious about this relationship,” a source exclusively tells In Touch. “It’s the real deal.”

Forever and always. “When they finally got a quiet moment alone, rumor has it Travis asked Taylor to marry him, and she accepted,” says the source. “Travis supposedly joked that it would have been nice if the Chiefs had also won, but getting engaged trumped everything.” Afterward, they shared the happy news with their families, although they’re waiting to make a public announcement. “This is a Christmas they’ll never forget!”

The proposal was romantic and traditional. Travis, 34, “spoke to Scott first to get his blessing, which wasn’t necessary but certainly appreciated,” says the source. “And then Travis got down on one knee and gushed about how much he loves her. Taylor tries to pretend she’s grown out of all that fairy-tale stuff, but the truth is Travis makes her swoon.”

So did the ring. “He had a gorgeous diamond set into a custom design for her — it’s exactly what she wanted,” says the source, estimating that the sparkler is worth about $1.2 million. (And, no, it’s not the opal and topaz ring she showed off at her 34th birthday party on December 13. That was a gift from her pal Keleigh Sperry, who’s wed to Miles Teller.)

Both of their families are overjoyed, says the source. “Travis immediately won over Scott, who never really had much in common with Taylor’s other boyfriends, and Andrea likes him, too.” And while the Kelce family have been “somewhat overwhelmed” by the spotlight on the high-profile romance, says the source, “they’ve been pleasantly surprised by how down-to-earth Taylor is. She’s really made an effort to get to know them, which they appreciate.”

She also fits right in at Arrowhead Stadium. “The players’ wives were kind of starstruck at first, but now they’re all besties with her, especially Brittany Mahomes,” the source says of quarterback Patrick’s wife, at whose side Taylor can often be seen cheering. “It’s like Taylor was born to be a football wife.”

Unfortunately, she may have to wait a while until she officially is one. “They both have such busy schedules,” says the source, noting that Taylor’s Eras Tour starts back up in February. “And she’ll be on the road all year. It will be hard to squeeze in a wedding, never mind plan one.”

But when they do get around to it, the bash is sure to be epic. “His whole team and her whole squad will be there,” says the source, who also expects multiple costume changes, A-list guests and Grammy-level performances. “It’s going to be the party of the century!” As for the maid of honor? “Her friends think it will be Blake Lively, Emma Stone or Selena Gomez” says the source. “Selena is the frontrunner.” Taylor served as her childhood BFF Brittany Maack’s maid of honor, and was a bridesmaid for longtime pal Abigail Anderson and newer bestie Lena Dunham, “so Taylor will definitely include them in a special way,” adds the source.

The couple can hardly wait for the big day. “Taylor is already working on her vows,” says the source. “Knowing her, they’ll eventually become a song!” Travis wouldn’t mind at all. “He’s the one guy she’s dated who isn’t worried about keeping their romance private or stopping her from writing about it,” says the source. “Which is one of the things she loves most about him.” They really are a perfect match. “Taylor’s definitely found the one,” says the source. “She’s finally ready to take the plunge and get married.”

And maybe even start a family. “Taylor loves being a godmother to her friends’ kids, but she’s never really talked too much about wanting to be a mother herself,” says the source. “That’s started to change a bit since she met Travis.”

Travis has made it clear he’s given fatherhood some thought. On his podcast, he joked that he has to start “breeding” so that Donna will root for him over Jason, who already has three kids. “And his dad wants lots of grandkids,” says the source. “But they’ll take it slow. They’re both still focused on their careers. Travis has two years left on his contract with the Chiefs, so he won’t be leaving Kansas City for a while. Ideally, they’d want to be settled in one place when they have kids.”

Luckily, they’ve got the rest of their lives ahead of them. “Taylor and Travis are both walking on air,” says the source. “They’re madly in love — and plan to be together forever.”