Everything hat others have said are good points, however personally I am not a fan of board breaking. I simply think there are just as effective ways to develop precision and technique as well as power, which don't have require breaking solid objects.
Heavy bag work for instance can is a great way of testing power, and as long as you have proper supervision and are assessing your technique throughout then it cannot harm your technique either. For precision, there are plenty of paddles or shields which test accuracy.
I have seen breaking be very good for some students' confidence, and honestly I have nothing against those who practice breaking- no doubt it has many good points to it. But it is not something which is essential to TKD, nor is it something I chose to devote much time to.
Looks good at demos though!