I want to be a Photographer (I'm 13)?

I would really like to be a photographer. But I don't know what I should take pictures of. I'm deciding between outdoor photos, sports, or weddings (Maybe in the future)

My camera stuff.

- Canon 550D
- Nikon D3100
- Canon 7D
I only have two lens', the 55mm-250mm, and 25mm-100mm?
What should I do?

Well first, May I ask why you have 3 camera bodies, and one of them being a different brand?

Photography is an art so make the best with what you have for now. Here are some tips:
Experiment with your camera to find the right setting for your preference (and practice taking shots inside and outside).
Light plays a huge role in cameras so pay attention to that.
Taking a subject next to a window is hard to do since the camera may get confused and darken your subject and focus on the light from the window.
Since I'm also new to photography, check out YouTube videos or google.
This website helped me a lot on effects you can do with the camera.
http://jfotography.net/tutorials-table-of-contents.php

Well to start with, just keep taking pictures. Start a 365 project where you take a photo a day for 365 days. That way you get into the practice of taking photos regularly and will really help you improve.

You already have a reasonable camera outfit, but at some stage you should chose between brands and stick to getting lenses etc for that one brand - Nikon and Canon are both good so I'm not going to make that choice for you. If you are using them to take photos you are already a photographer, as is everybody else with a camera. So get to know your equipment and what sort of photos you like to take. Don't specialise at this stage. If you want to try to earn a living at photography you should probably study at college. You will certainly need guts, determination, staying power and 'people-skills' - they will be more important than your camera skills.

You should make a Flickr account so we can see your pictures. Just practice taking a picture of whatever you like!