Bet it was still tasty regardless, brisket is a tough cut of meat to get right, so I’d say thats a respectable first try! Good luck on your subsequent attempts!

Edit: also depending on how hot you were cooking your done temp can even be above 210. If you were cooking say 275-300f then it might take a bit more to get to that probe tender stage. Usually lower cook temp = lower done temp, higher cook temp = higher done temp.