I'm not a lawyer or a magistrate but I've spent the better part of half a century reading court reports (and, during my journalism training, done a bit of court reporting myself). I'm also not a gambler but, if I was, I'd be prepared to lay a very heavy bet on you avoiding prison. (Even if a custodial sentence is passed, which seems unlikely, it would almost cetainly be suspended).
BTW, I also spent 15 years teaching 15yo lads. I'd actually be worried about any who didn't 'mouth off' at their parents occasionally! It's normal. Learn to live with it!