This most recent DUI will likely count as your second DUI. Depending on the County (and more importantly) the Judge, incarceration is absolutely a possibility.
You have several issues to deal with.
First is your driving privilege. With a .18 BrAC (Breath Alcohol Content), you will be facing at a minimum either a 90 day complete suspension of your license (or privilege to drive) or interlock device (breath test hooked up to your car) for a minimum of one year.
If you are facing DUI charges and want Scott to take a look at your case, complete the DUI Case Evaluation Form and Scott will contact you.
Online classes are typically NOT accepted by the Maryland Courts.
There are, however, several providers that will conduct classes by telephone and/or through Skype.
There are also providers that have alcohol programs that can be completed in one weekend (provided your assessment is appropriate).