I don't know about Illinois, but you already did the right thing and got a lawyer. I had a 26 over in VA, which is also a misdemeanor, and I did not hire a lawyer.
The judge barely even let me speak, ended up getting convicted, $1000 fine and lost my license for 3 months... He said consider myself lucky I wasn't in jail for the next 3 months as he could have put me in there for a year.
Oh and this was the first and last ticket to go on my record. I had to list it on all of my job applications as a convicted crime, luckily most MD companies laughed when they saw it.
Ask your lawyer what to expect.