@sims_gamer_fan : Hello Izzy,
As @THISaint stated, most of the testing available before a game launches comes in the way of beta testing, which is when a game is open to a portion of the public (or sometimes everyone if it is a public beta) so that they can help find issues. At the moment, I think we have FIFA World in open beta, but with the E3 conference tonight, maybe we will soon have more!
Otherwise, our Quality Assurance testers are the ones doing the brunt of testing. However, it's a job like any other so it requires you to be of age in your country. If you're in 7th grade you still have a way to go. 🙂
EDIT: Before you think about a job, we also sometimes have positions available for interns and students. This means that again, you'll probably have to be 18+, in all cases here is more information on our program: http://careers.ea.com/internshipsco-ops
