What are some jobs I can do to train myself for a career in photography?

I am only a teenager, so it cannot be an official job.

Like taking pictures for friends, at birthday parties, etc.
I'm not talking about official jobs.

Just because you are a teenager doesnt mean it cant be an official job. I mean, you could start out at any number of retail locations. You could do things like you mentioned like pics for friends or parties or weddings or individual model shoots. You can post on local sites or the newspaper or fliers. However, being that you are underage, I highly suggest you screen everyone you see and possibly have an adult with you or at the very least let someone know where you are and who you are with and verify legal ids.

Try getting on the year book or newspaper staff at your school or local paper or local college campus, things like that. And freelance, ofcourse with any number of online websites, local places and hobby magazines.

You should talk to someone about the legality of pic rights, royalties and copyrights, etc. May or may not be something you need to worry about depending on what you are doing but it IS something you need to be aware of.

apprentice at a photo studio (yellow pages), work at a camera store, work at a photo processing (high end enlargements) shop.

The photo studio would give you the best bang for your buck, and give you invaluable lessons in lighting and light placement, use of reflectors, focal length, photo shop, etc..

If you are a female (which by your avatar I am assuming) you will have an 80% better chance at getting an apprenticeship with a local photographer than a guy would.

So ... remember, the key is to be willing to work cheap (photographers are notoriously cheap) and go to apply in person. NO PHONE CALLS.

Get out the yellow pages and get started!

You can't really train for photography. You need to learn all the aspects of photography such as ISO, aperture, and shutter speed. Experiment with different settings and find out how to use the camera to its fullest. After you can fully use your camera you can practice shooting your friends and after you get better you can set up a little studio and take pictures for cheap.

Practice, practice, practice

And take advantage of online apps like flickr to gain exposure to your favorite inspirations.

You have a great question! You are never too young or old to love photography & more importantly to make money from your art. Now, I will say, I've designed some awesome video coures (business success essentials, Photoshop (you name the feature tons of classes) and everything you could want to know about how to take better photos). For you this is the course plan I would suggest ($15 student pricing for xTrain)...

1. start with the shooting techniques with Rick Sammon...
http://training.xtrain.com/serial/show/2...

2. Then start with good solid camera & photoshop techniques with Rob Sheppard..
http://training.xtrain.com/serial/show/3...

3. Take off with Photoshop! There are many classes, Ben Willmore, Russell Brown, etc on xTrain.com that will get you into the "how to shoot & process" pictures professionally...

4. upload your final portfolios, xtrain offers a realm for you to have your portfolio reviewed and rated, but flickr is a great place to publicly announce your work...

5. Have FUN! The more fun you have, the more niche you'll find, the more MONEY you'll make!