I'm not discouraging them. I'm saying that age doesn't matter. Completing an app is a laudable accomplishment for anyone. Emphasizing their age, if anything, makes light of this accomplishment because it can come off as patronizing. I think that it's great that they made an app, but their age isn't important.
I think age is relevant for this post. Otherwise nobody would be really interested in reading a post about a new release, everytime a programmer in this website comes up with their new app. So I think the most important thing is that he is just 14 years old provided that the quality of his work is decently acceptable.
PS: don't be like that to your own kids, cuz you will be hated as a father, I can guarantee you that.