Hi 1stTimeMommy
Please readjust your thinking just a bit. This is very very important. You state that this meeting is to discuss his shortcomings. (You do also say it is to discuss what your hopes and goals are for him as he grows up). This frames him in a negative light. Which I'm sure you don't mean. He's probably the light of your life. So, talk about the part of him that is autistic in the same way (yep, new diagnosis, you're still getting used to it... I know) that you talk about the part of him that is really (good / easy/ funny etc) positive.
It's a bit of a semantic argument. But please please please never say "shortcomings" again. Choose whatever words you want. When I had an IEP meeting for my daughter her advocate told me this was the meeting to discuss "the support services for which she is entitled that will enable her to be the best kid she can be". It was not to discuss her shortcomings. Quite frankly.... your son doesn't have any. He simply has areas in which he needs some additional tools in order to do his work in life (not to minimize - I understand the gravity).
The only advice I will give is that you should treat this IEP meeting the same way you treat your OB/GYN appt. Or the appt when you are sick. You are an EQUAL and you are the advocate for your son. It's not "these people" sitting around a table telling you what they'll do. Establish it as a partnership where you all want to find the best solution for you son to maximize his care. The same level of participation that you would have with your physician about your sinus infection or birth control (but I know my sinuses and I don't think xyz is the best course of treatment... explain to me why you think we should do an iud instead of the pill.... well what if 123... when could we re-evaluate if I don't feel better etc etc etc.) is the same level of ownership and partnership you should have at this IEP meeting.
Typically you re-evaluate an IEP annually, with a complete re-test at the 3rd IEP year mark. That may be IL state guidelines though. And autism may be a bit different IEP, if it also includes a 504. I'm not sure about that.
Also remember that he doesn't have to go to the local elementary school in order for them to provide services to meet his needs and help him succeed. That's part of what your home owner taxes are for; to fund those programs. So, even if you decide to attend another school you will still get services through your local school. Which means establishing a partnership that is that much stronger.
Good Luck!!!!!