You are so not alone. You would be surprised (or maybe not) at how many young girls say almost the exact same things in the same way. Sometimes I'm torn between telling them to start by getting some training and telling them to just go get a headshot and go to some casting website and start submitting. But reason wins over me and I have to tell you that if you really want to be an actress, you should first put your big rush to do it to the side and slow down. Build your base first.
You might have heard in school when you talked about Abraham Lincoln, that he is the author of a famous quote. He said, "If I had three hours to chop down a tree, I would use the first hour to sharpen the axe."
If you don't sharpen your axe first, there will inevitably be a time when you will have to stop chopping and sharpen it, so you might as well do it now.
What does that mean? Get some acting training. Find a good school and a good teacher to help you learn how to act.
While you are doing that, try and understand what it really means to be an actor, what actors do...really while they are trying to get work, how little money most actors make, why actors struggle to make ends meet and how successful actors are able to continuously get work. You need to learn business skills, networking skills, communication skills and a lot more.
When you decide to become an actress, you are making a decision to run your own business. Now I know you are young, but if you can start to grasp these concepts now, WITH THE HELP OF YOUR PARENTS of course, you will position yourself ahead of your competition.
On the other hand if all you ever aspire to is to work background work on Disney Channel, then don't worry too much about all that stuff I just said and just go and try and get extra work. That's fairly easy to get considering that the majority of all acting work is background work and smaller roles. But you have to know that if you really want to make a big splash as an actress, sooner or later you will need some real experience. Extra work is great in my opinion at the very beginning just to start and see how things are on set and how real actors prepare and perform and to see how set directions are given, but it will not make your career.
The thing is, you can do both. You can go to school, take acting classes and still work as an extra while you are learning the craft.
At any rate, have a look at this page on my website for aspiring actors. It has 23 helpful tips on different aspects of starting an acting career including what your first steps should be, 23 benefits of taking acting classes, about getting work on Disney Channel, how to get an agent, how to choose a school and industry resources you need to know about..
http://www.actingcareerstartup.com/teen_acting.html
Good luck!
Tony