Is my cat mentally retarded?

I got my kitten on may 14th 2011, shes 14 weeks old. She is a very, very lovable and affectionate kitten. i love her so much but i honestly think she is mentally retarded or has autism or something. I know that sounds mean but i want to know, maybe she just has failure to thrive syndrome. Okay so she smells, she doesn't clean herself properly, she's slightly cross eyed, very frail (but shes very well fed) she can not meow, she seems to have poor depth perception, she's not aggressive either. she doesn't seem to be able to fight for herself with our older cat when they fight playfully (who acts very motherly towards her). She doesn't know how to use her claws. she walks/runs clumsily almost as if she's drunk. And the weirdest thing that happened yesterday was that i had JUST cleaned her litter box completely with new litter and all and when she she approached it, she quickly backed up frantically, and then sprinted up the stairs to my parents bathroom and pooped in their bathtub. Someone please please tell me if they think this is odd or just random cat behavior!! thank you :)