"It took Kourtney months to get to where she is right now," a source tells PEOPLE

By Aurelie Corinthios
Updated April 15, 2016 04:00 PM

brightcove.createExperiences(); Things are looking good for Kourtney Kardashian.

As the reality star gears up for her 37th birthday on Monday, a source tells PEOPLE Kardashian is “doing great.”

“It took Kourtney months to get to where she is right now,” says the source of Kardashian, who endured a difficult breakup with Scott Disick last July after nine years that saw them start a family of three children.

Though “last year was very tough for her,” the source says she acts “happier and confident lately.”

According to the source, Kardashian’s “main focus” is still her kids, son Mason, 6, daughter Penelope, 3, and baby boy Reign, 16 months, whom she shares with ex Disick.

Indeed, Kardashian and Disick, 32, have been making their kids a priority and spending time together as a family lately. Most recently, Disick joined Kardashian and the rest of her famous family on vacation in Vail, Colorado, and the source says Disick “was very well-behaved” on the trip, “just focused on his family.”

“He still goes out in Los Angeles and drinks a bit, but he seems to be able to control his life,” says the source of Disick, who completed rehab treatment in the fall.

Adds the source, “[Kardashian] and Scott are in a good place. They are getting along and very friendly.”

As for rumors they might be getting back together? According to the source, Kardashian “has no plans to get back with Scott right now, but who knows what will happen in the future” – a sentiment Kardashian herself echoed during an interview this week.

In the meantime, Kardashian “is dating a bit and having fun,” though it’s “nothing serious,” says the source.

And having fun she is! A separate source told PEOPLE Thursday Kardashian and Justin Bieber, 22, have “hooked up a few times” recently. (Multiple sources previously confirmed to PEOPLE the two were hooking up last year).

“Justin thinks it’s cool that she is older and hot. She isn’t clingy and has her own life,” the source said. “There are no bad consequences for Justin to hook up with her. She is very easy going and just makes it fun for him to be around her.”