It is a sign of autism when a toddler ignores an adult's eye contact, but LOVES other kids?

She is 21 months old and every time we see her I can't get her attention for anything - she won't respond to me talking to her or calling her name, will almost never give me or other adults eye contact - maybe a split second at the most. But she LOVES other kids and will chase them, squealing, touch them, loves to look at their faces and almost even get right up in their faces. She is the sweetest, happiest, little girl and always squealing in delight.