Just remember slower = better at this point. Slow down and perfect a skill, the speed will come with practice. Get a couple round files in different sizes and a good triangle file or 2. You can use these for your jimping, filework patterns and you can also use the round files to establish your plunge line for primary bevels. Most all of us use a dremel type tool for one thing or another. The files in my opinion just provide a level of control you can't easily get with a dremel.
Unless you can get a steal on a good used grinder, I think the craftsman 2x42 is about the best buy for the money under 6 or $800. Yes, yes, I know it is screaming fast and I just said slower is better.

I see right now sears has them for $152.xx and free shipping. I would go ahead and get a couple packages of the belts to take advantage of the free shipping. As others have stated, it also might be a good idea to go back to files even for the bevels for a while. I think you will be pleasantly surprised with the results you end up with. Even though I have always used a grinder of some sorts, I am considering doing some with files myself. I think it will improve my skill set and open some options for some blade designs that would be near impossible with my current set up.
While ordering supplies I would also advise ordering a couple respirators and some safety glasses if you don't already have them. I still catch myself without the mask occasionally. It is easier to start out using the proper safety techniques than to break old habits.
Some comments may seem blunt or harsh though I can say they are not meant to be. If no one ever told us what we were doing wrong, we would never improve and you seem to get this.
Good for you on picking up a hobby that most of us waited until we were at least twice your age. :thumbup:
Chris