Is it possible that Helen Keller was a damned liar?

Honestly, why would someone spend their whole life just to lie about something like that? And in order for that to be true, she would have had to come up with that idea early in her childhood, when she was like, three. Now really, how many toddlers do you know that would be able to think logically enough to pass herself off as a blind, deaf, mute in order to gain fame? Their minds just don't work like that.