I have a little martial arts experience, but nothing in sword fighting. I'm clumsy. Uncoordinated. And if lightsabers were real, I'd have seriously maimed or killed myself by now.
And it's only been a week for me.
The Terra Prime Lightsaber Academy videos are a great place to start. I would say, as a beginner myself, that if you want to specialize in any form that you start with Form I: Shii-Cho. This is the form taught to Padawan Learners and Younglings for a reason. It teaches basic techniques and movements, as well as sets a foundation to later build upon. Become a master of Shii-cho or move into another form such as the defensive Soresu or the acrobatic Ataru.
Oh! And get a pair of gloves! Nothing fancy! Just something to shield your hands while training. You WILL thank me later!