初めまして！

初めまして！私の名前はケヤッタです。アメリカから来ました。私は１５歳です。日本が大好きですから日本語を勉強しています。私は英語が話せて/分かって、少し日本語も話せます/分かります。日本語はあまり難しくありません。よろしくお願いします！＾＾

Name+と言います is also common

アメリカの出身です is more formal, instead of using country+から来ました.

Grammarians (purists at least) say that the potential form in Japanese should only take が and therefore say 英語が話せる but in reality many speakers use the accusative particle and say 英語を話せる, using を is considered a mistake by many but also accepted by others, so keep that in mind.

When using から the usual order is different from English, i.e. ''I can't go to the movies because I don't have money'' becomes ''because I don't have money I can't go to the movies'' in Japanese. It doesn't mean the English syntax isn't possible, it is, but that's rather used in speech when what's attached to から pops up later in the mind of the speaker, this happens with many other things, like saying 遅刻したね、彼が, instead of 彼が遅刻したね. That's colloquial.