as it's been said, magick has no colour. it comes down to the user's intent that makes it 'white' or 'black'. [positive or negative]
what is your path? do you just want to cast spells, or have you decided to convert to Wicca or Druid or something? knowing what it is you study can help you get a teacher.
onto the revenge though, magick can do this, but it's not the wisest move to follow this path to intimidate or turn the tides onto another. to quote an article i like from about.com
"If people are mean to you, they're going to continue being mean even if you're a witch. If you're interested in becoming Pagan just because it sounds spooky and scary, that's not a great reason. In fact, you could find yourself having even more problems if you walk around telling the people who are harassing you that you're now Pagan."
point is, think before you cast, and if you're just starting out on this path, do some real soul searching before continuing on. you would hate to spend a lot of time and money on what amounts to a phase. sad to say, many people around your age hear about paganism and magick and think it'll make them different, or it's really cool, and they switch without really thinking about it. as they get older, they grow out of it. i'm not saying that's what you're doing, i was 15 when i started my year and a day, but some people join for fickle reasons and after a few years leave the craft. [many times giving the serious practitioners a bad reputation] so just think before you go any further. if you can meditate, do so.