It also depends on your level. If you are just starting out and do not yet know any Japanese, it probably doesn't matter if your teacher is from Japan or not. You can learn about basic Japanese grammar, essential vocabulary, and hiragana/katakana from a native speaker, a foreigner who learned already, or by yourself using a textbook and online materials. You should make sure you understand how to pronounce the basic kana at this level, since it might be hard to break habits later on.
At some point, however, interacting with a native speaker will help a lot. I have found that a native speaker who has at least some ability to speak your native language is helpful, so they can explain concepts that you are having trouble with.