DeeDubb
Veteran
There are better cubes, tutorials and algs now, so it's becoming more and more common for people to progress very quickly.
Not this quickly though.
Honestly, I could buy the 3x3 at 17 in 3 months, but the 2x2 and 4x4 improvement at the same time is what makes it very unlikely to me. I think he's either completely lying, or maybe calling his PBs his average as a mistake or to sound impressive.