Kai Trump’s officially tossed the cap in the air -- and the Trump fam rolled deep to celebrate the big graduation milestone!

Check out our gallery and the clip ... Donald Trump Jr. and Vanessa Trump stepped out Friday night for a cozy family dinner honoring their daughter Kai after she graduated from The Benjamin School in Palm Beach Gardens, Florida.

Fresh off turning 19 just days earlier, Kai looked all grown up while celebrating with family and close friends -- including Tiffany Trump, Michael Boulos and Bettina Anderson.

Oh -- and Tiger Woods also showed his support by attending the graduation ceremony earlier in the day too.

And while he’s not pictured here ... goes without saying, grandpa Donald Trump has gotta be one proud dude right now!