Could my baby be autistic...?

my son is 21 months old next week, he crawled late at about 10 or 11 months he walked late at about 18 months, now hes 21 months old he makes a lot of babbling baby noises and screams a lot but he hasn't said one word not on not mommy daddy oops look nothing,he gets frustrated if he has to finger feed himself and a lot of times would prefer not to eat at all he lives in a household where hes talked to a lot and is the center of attention so i just don't get why he wont say anything.i know kids his age that have ab out 15 words in there vocabulary and he doesn't say anything when i try to read to him he would rather throw the book around,i took him for a hearing test and they said his hearings fine,ive tried everything including your baby can read which DOES NOT WORK! at least not for my kid....im on my last leg with this.li cry often due to the fact that every body tells me he'll come around but IM his MOM i know there's something wrong could it be autism?mothers with children whom have autism are strongly urged to respond,please no criticizing remarks telling me how ridiculous i am for expecting so much from him ,thanx....