Things to think about

When I was in year 5 of this business, I took a class through the Small Business Development Center called New Venture Training. It was a class designed for those contemplating owning a business/growing a business and we all wrote our Business Plans. The class was great fun, we learned alot and got to bounce ideas off each other, I can't recommend it highly enough. They do have some scholarships available and I do encourage you to look into it.
They also had a financial class that went along with it, that was 4 sessions I believe. Anyhow, the ONLY thing I took exception with, was the instructor said "if you arent perfectly healthy, if you even take an aspirin now and then, being self-employed isn't for you". I think if you have any major health issues you need to give a little extra thought to how you'll work around the issue, but I wouldn't let it stop me!
I think the main thing is to know that if you do decide to go into business, it will require dedication and sometimes even sacrifice. You will need to have great self-discipline, it all falls on your shoulders. But the thing is, for me anyhow, the rewards FAR outweigh the challenges. and remember "Nothing is impossible to a valiant heart" :-)

Biz Plan

You know the old saying, if you don't know where you're going, how will you get there? A Business Plan is an essential ingredient in your success. Things you may not have thought about, as well as really mapping out how your company will become successful. There's a lot of information in your plan, and if you are ever serious about getting investors or other financing, it's required.
There are a few organizations that actually have programs to help you do this, I believe the Women's Initiative out of Oakland has a program, and the one that I graduated from was from The Small Business Development Center. Here's a link for you to get more information on that http://contracostasbdc.com/ (you'll have to copy/paste, I couldn't get it to click right) It's called New Venture Training and is an intensive 12 week program. Don't let the cost scare you off, they will consider a scholarship for you, that's what I did.
I have found the information provided to be very valuable and I still refer to my notes even now. If you're serious about your business, I heartily recommend your taking advantage of this informative program. (If you call, and speak to Jeff Hall, tell him Carla the SOAP LADY sent you)