Could my 18 month old be Autistic or suffer from "Profectionism" ?

The other day a friend of my mothers was over and noticed my sons behavior and told me that her grand daughter was Autistic and that my son had a lot of the behavioral qualities. I am a first time mom so I just ped it off as just his little quirky personality, but now I don't know what to think. He is kind of a "loner" and really doesn't care too much about what kids or people around him are doing, he's just happy playing on his own with his own toys. He likes things to be in their place, and if I move his toys around to vacuum he immediately puts them back when I am finished and if it's a larger toy that he can't move he gets upset until I put it back. He also will not leave the house without his shoes on, and if we are leaving to go somewhere very early and I wake him up just to put him in the car in his pj's he cries for his shoes. I am a stay at home mom and he is basically an only child. He has a 9 yr old 1/2 brother that comes on the weekends and he loves following him around and copying what he does. I've always figured that he just had a strong little personality about things. And as far as the not wanting to play w/ other children, I always thought that toddlers didn't start to have friendships until around 2 years old. He is a very affectionate toddler and likes to cuddle. He also says a wide variety of words and I believe he communicates to me and others what he wants pretty well. He will point to things and if he can say what it is he will ask for it by it's name ie. snack, cup, bath. I really don't believe he is Autistic but I have never heard of "Perfectionism".