I'm not sure I agree with the standard advice handed out here to hire first. Hiring is EXPENSIVE, and I'm underplaying it. For the cost of 4 or 5 week-long hires on various boats to see what you like, you could burn through the price of buying a second-hand entry-level narrowboat.
The forum isn't that good at general questions like does anyone have advice for a beginner. You're far better off starting a series of threads each asking a specific, focussed question e.g. "How much should I spend to get a decent second-hand narrowboat suitable for a beginner?"
Or better, go through David Mack's post just above and post answers to each of the questions he poses, then people here will have a better idea of what to advise.