There is a similar thread titled "help" in this section, you may want to read that.
As for deciding what to do, it depends on what you're looking for, which MA fits your philosophy, and how comfortable you feel in that art and in the dojo. Try all three if you can, ask the sensei if you join in a couple of classes. Ask the students what they think of their respective MA.
Keep an open mind and remember that these are three different MA's with their own strenghts and philosophies.
Good luck and have fun