There are three classes to choose from in Life is Magic:
Each class has their own strengths and performs well both solo and in a party, so select a class based on the play style that you prefer.
There is no way to change characters once you start unless you email Red Robot for a reset. http://forums.lifeismagic.com/viewtopic.php?f=4&t=626
Go to the Red Robot Labs Support Center and submit a ticket requesting an account change.