I'm exactly like you, I am 13 and have tried from a young age. Trouble is my parents are against or at least don't believe in magic, so I have to try in secret.
It is everywhere just look at life how do flowers grow with the energy from the sun and people have energy too that can do amazing things like that and i know about the family thing my whole family is Christian/Catholic and they are don't like it but just remember no one can tell you how to live your life
http://www.spellsofmagic.com/coven.html?coven=628
http://www.spellsofmagic.com/coven.html?coven=3
http://www.spellsofmagic.com/coven.html?coven=6
Just join one of these and they can help Teen witches is helpful for starters and The dark and light is great if you want to learn dark magic like things which is easier but not as much use except well just like it sounds
A great way to start with anything is to take some paper roll it in to a ball then place it on your left hand then place your right hand a little over your left hand the focus on the energy moving from your left hand to the right and hitting the paper and it will start shaking by removing the balance its simple and easy to do with little around the house stuff
A lot of magick is blind faith and trusting your instincts and intuition. It sucks, I know, because I went through the exact same thing, trying to prove to myself it's true. But then I realized, just finding a site with hundreds of people who have the same beliefs as me has to count for something, right? (I was self-taught)
And you may very well have been successful already...magick is subtle, it's not the flamboyant thing you'd think it would be. Some of your spells might have worked, just not as drastically as you think! Don't give up, just keep trying and all efforts are rewarded :)
Tannerr, age doesn't always matter. Just because you're 13 or younger does not mean you can't learn or practice.
S_D, as said before magick isn't flashy. Some spells take days, months, or even years until you have effects, and almost all effects aren't seen with the eyes. They're more felt. For starting out: Learn and practice the basics. They'll give you a nice little foundation to build upon.