I don't think chinese is so hard to learn, but if you study with a "Not good" teacher, and you have no idea what's wrong with that teacher...Then..you gotta trouble.
Many chinese school they offer the chinese lessons, but most of them not really care of that class/students. I really don't like it. It's very important to have the GREAT teacher at the first time. If you didn't, then you should find a GREAT teacher w/t patient to correct you.