Well, it depends on if what you're hoping to accomplish.
You our could try to find a language partner. That is someone who speaks the language you'd like to practice and who also wants to practice the language YOU speak. You can do this for free. You would speak with someone via Skype -- half the time in one language and half the time in another language.
You could also pay for lessons. Italki has two types of teachers: professionals and community tutors. Community tutors are usually cheaper, but they are not certified as a teacher. They do not generally provide formal lessons. Professional teachers are certified as teachers. They provide formal materials and a lesson plan, unless you chose informal tutoring. They are also usually more expensive.
it may be the mother in me, but as a female teenager, I would personally suggest that you find a female language partner if you decide to do the free language exchange. There have been some reports of women receiving odd messages, so keep an eye out and don't feel obligated to reply to anyone, add them as a friend, or give them your skype information. If you chose a paid tutor or teacher, just look for someone who has good reviews and watch their videos to see who you might be most comfortable with .