M.,
I do not have a child with Asperger's but my husband has a mild form of the syndrome. More importantly, I am a child/school psychologist who has worked for many years with children diagnosed with this syndrome.
What you have described does not sound like Asperger's Syndrome for several reasons. First and foremost, you do not describe a circumscribed interest. For example, my husband LOVES "The Simpsons"- he quotes it, refers to it and watches is regularly. The children I work with often are referred to as "little professors" surrounding very specific topics such as dinosaurs or engines. They can tell you everything and anything about the topic and will continue to talk and talk and talk w/o reading the social cues from the other person that the topic is boring or that they are no longer listening.
Second, your son reads social cues. The children I work with need to be taught the "mechanics" of social nuances and need to practice. I literally have "face" flashcards and we practice them like others would learn math facts. With my husband, I often have to explain to him why something that he has said is offensive to the receiver b/c he cannot perceive their reaction.
Third, folks with Asperger's are entirely black-and-white. There is no grey area and they cannot comprehend when things are not defined. Math and science tend to be their preferred subjects and literature just isn't enjoyable! Lots of engineers have Asperger's... that's the mindset.
Finally, people with Asperger's Syndrome thrive on routines and absolutely must have them to function. If a routine is broken without warning, these individuals cannot adjust. They melt-down, act-out and need a lot of help to return to a calm state.
Unless your friend is a doctor, don't listen to her. Yes, people with Asperger's often have sensory needs, but Asperger's is a syndrome, meaning that there is no test for it. There are a series of behavioral hallmarks that must be present for a diagnosis. If you are really concerned, speak with the pediatrician.
Educationally, this is irrelevant as a preschool student. All children who meet eligibility criteria for CPSE services as they age-out of EI are considered Preschoolers with a Disabilty (PWD). Your son's needs will be reviewed to determine whether or not he continues to require OT services. If he is not eligible through CPSE, speak with the pediatrician and request a script and get the OT through your insurance if possible.
To tell you not to worry is like telling you not to breathe, but unless you are leaving out major behaviors your son does not meet the DSM criteria for Asperger's, but he may have Sensory Integration Dysfunction- or he could just be a "quirky kid" who needs some extra help.
If you have further concerns, just message me. I live with Asperger's each day with my husband and work with several children diagnosed with the syndrome. It's a challenge, but once you understand how they think and react you can work through it!
Good luck at your meeting and remember that your son will get the services that he needs with or without a diagnosis.