Besides his age, the main reason for this story is probably the fact that he is a homeless teenager and that it is very rare that kids with such a background excel. He cannot be the only one who is obviously highly gifted, it is a tragedy that these children are deprived by the system to be sufficiently empowered and thus sustainably break the cycle of poverty.
This, and the fact that california is planning to eliminate or drastically reduce the gifted education program in calculus in the name of equity!, which essentially will deprive especially gifted poor kids of even the slightest chance to get noticed, makes me sad and incredibly angry at the same time.