The comedian celebrated her 44th born day Sunday ... and it looks like it was a musical affair. She posted a clip of herself performing in this big cabaret-type show at a private shindig where she was front and center in front of a lot of friends.

Her caption reads, "Happy Birthday to me!!!!! I am ready for my next chapter in life." TF goes on to share she has more original music coming, not to mention another book ... among other ventures.

She adds (somewhat cryptically) ... "I keep my promises anyone that knows me knows that. It might take some time but I always keep my promise. Just ask God."

While she didn't specifically mention her DUI from a couple weeks ago, it sounds like she might be touching on it here. Not just that, but Page Six reports that Tiffany was actually among Paris Hilton's many famous guests at her "Slivmas" holiday party earlier last week ... and they say she was completely sober there.

If true, that's big news considering she got arrested for allegedly drinking and driving (again) after a night out in L.A. -- this, of course, about a year after she got arrested for the same thing out in Georgia. If she was steering clear of alcohol at Paris' bash, it stands to reason she might've done the same at her own.

TMZ broke the story ... Tiffany was arrested in Beverly Hills after cops say they found her sleeping at the wheel and blocking the road with her car. In the end, they felt they had probable cause to take her in for DUI ... and did exactly that.

Less than 24 hours later, she was back onstage and performing yet again -- this time at a Laugh Factory all the way down in Long Beach ... where she jokingly addressed her arrest.

She might've been laughing about it then, but it's a very serious matter ... and prosecutors in Georgia have already signaled they want stricter restrictions on her as her case there plays out -- including forcing her to stay off of alcohol consumption.