D.,
I usually tell people to trust their guts, but often, we do not know what to be concerned about. I would find out why your child is not making eye contact and not seeking joint attention. We have had the most sucess with developmental pediatricians for our children with autistic spectrim disorders.
Try not to look for the "signs" that prove that she does not have it, you may be very wrong indeed, there is no one thing that they do that will disqualify the diagnosis, many children walk and talk and still have an austistic spectrim disorder. Get you information from people who diagnose it everyday. Check the list on autism speaks web site, it is very good, but do not count on your regular pediatrician knowing squat about it, many don't have a clue, and waiting to "see" is the absolute wrong thing to do, the earlier you intevene, the better the outcome, period.
Our children with autism had signs from the day they were born, but we did not know what we were looking for. You have your first warining sign, take it seriously, and at the very least, do not ignore anything else with this child that makes you say "is this typical?" Any feeding problems, sensory issues, sleeping issues, anxiety and fears(including being clingy) slow fine motor development, slow gross motor developement or awkward gross motor skills could be early signs.