Gabriel, please know that the best way to learn a language is to use the language on a daily basis. More than what the school teaches you , while you are in an English spoken environment you would meet such people and converse with them in English.  That would contribute far more to your level of English thag would by the grammar lessons etc. As you know in every state in US the English and vocabulary is slightly different. And in my home country we were taught British English and sometimes I get confused with modern day American English.  But yes just to stress here to you that speaking and practicing is gonna help alot more than what they teach u in schools. I don't think ud need to go all the way there to learn English many have successfully done it from home. Either way wish you all the best in your up takings.