hi Kari, going off auto is AWESOME! (from a sometimes-professional photograher, here!) Here are my thoughts:
1. At first, your pictures will get worse. Sometimes, WAY worse. But as you learn & improve your skills, they will get "as good" as your auto pictures, and then...BETTER! Depending on how fast you learn and how much time you are able to commit to it, this may take several weeks or several months.
2. You don't really NEED to go off auto. If you're happy with your photos now, then that's fine.
3. By going off auto, you will be able to control many things in your photos that were previously left up to the camera to decide. For example, many portraits look best with a shallow depth of field. This is when your subject is sharp and clear, and everything behind them is pleasantly blurred out. If you shoot in manual, you can control the aperture and get your background to blur. (In this case, you would use a wide aperture to achieve the shallow depth of field look.) You can also decide whether you want a motion shot to look like motion blur, like soft running water, or whether you want to freeze the motion and see individual droplets of water. (You would do this by changing your shutter speed.)
The reason I say that photos get WORSE temporarily (only temporarily!) is because you have to do a lot of playing around with your camera settings, and do a lot of practice and trial/error to learn what works & how to achieve it. Yes, there are defined things to do to get the shots you want. A very blurry background is achieved with a very wide aperture, like a f/1.8 or f/2.5 or similar. However, knowing where to place your subject to ensure there's no backlighting, knowing how far to stand, knowing where to set your focus point, knowing whether or not to use fill flash...these things take time and vary a bit with each individual situation.
About learning: I'd say to check your local community college or parks & rec division of the city. THey often have continuing education or "fun only" classes for adults. (I used to teach at my local parks/rec and it was fun!) I also LOVE reading photo books and just searching the web for tutorials. I'll look up a few fave books & sites & post in a second message.
good luck!
J