Without seeing your file, it is all but impossible to render a valid opinion. You should not and cannot provide the level of detail. What I can advise is to ask why the pd believes you should go to trial. They may not have a ton of time to explain details due to case load pressures, but should be able to articulate a reasonably quick explanation. Ultimately, it's your choice on how to proceed, but if the pd can give some direction on why they feel you should take it to trial, maybe you'll agree and be convinced.
Attorneys make their recommendations based on experience and the facts in your case. The easy way is usually just taking a plea, but that's not always the best way. Sometimes the chances are good enough with a trial for a win so it's a no brainer. Pd's don't have time to waste, so if they feel strongly about it, that might be a good sign.
That deal doesn't strike me as fantastic, but I'm not looking at your history.
Perhaps I'm just overtired, but if this is a first DUI, you should be eligible for supervision (maybe that's what you meant by probation)?
If its 18 months supervision plus fines, that changes things a bit.
Talk to the pd. I bet there is a very good reason they think you'll be better off going to trial than taking a plea. I explained to a client today why, in his case, a plea might be a good idea in under ten minutes and he asked a lot of questions. I always make sure my clients understand that it is always their choice.
It is impossible to give a complete answer based upon the sketchy facts presented here. However, before you make any decision, you should ring all your paperwork to an experienced DUI defense attorney and discuss your options. Do not go to court uneducated. Best - Do not go to court unrepresented, especially in Champaign County.