No, I think it would be hard to overdose on it. You'd most likely end up with just an acid stomach.
In the late 1940s, when it was first used, they were giving people 16-20 grams a day, with no dietary intervention. At 15, you're taking less than 1 grams a day.
When I had talked to Al Czap about this years ago, he had mentioned that he had an elderly lady who misread the recommended dose and instead of taking 750mg a day, she was taking 750 gelcaps a day and getting a bit of an acid stomach.