Hey, Blairstel42. Lessons will accelerate your learning process. Case in point: if you'd had a lesson before you bought your gear, you probably wouldn't have bought an rpm. Not a bad kite after you've been through the learning curve on a bow-shaped LEI, but the rpm isn't really a good kite for learning.
If you want to save money, take on more risk, and drag out the process of learning to kiteboard, then you certainly can teach yourself. But my advice would be to invest in a few lessons to save yourself some time, learn safety, and avoid some of the aggravating trial-and-error that goes along with trying to learn on your own.
If you decide to take lessons, try to pick a good instructor and go out on a day with decent wind conditions. After a few lessons, you'll still have a lot of independent trial-and-error practice time (water time) to make headway, but you'll have learned the basic foundation that will allow you to progress much faster on your own.