I suspect it's that 5ft 2" is quite a bit different from 2ft. If you weren't autistic you'd have gotten that
Oh listen to the wee man now "Ah...ah...ah...I'm not 5 foot 2!" Are your arms and legs in proportion with the rest of your body?
There's no definitive answer to this one, it seems. (As in a government web site or statistics from a census or something). [The average height of an adult male in the UK is 5'9"] seems to be the most often quoted statistic