I sometimes wonder if there are more people who start taking English classes in January than in September. September is a more logical time to start classes: after you've been through school for almost twenty years, September feels like the logical time to start anything that is new and academic.
January, however, is a time of new beginnings, a time to start clean. So it's probably no surprise that a lot of people prefer to start classes in January. Why not? If you're already thinking about new changes for the new year, why not start (or re-start) learning English?
I think that anyone who has the guts and dedication to learn English well should be congratulated. It's a difficult task, but it can give you many rewards. That said, there are some things that English cannot do.
English will not save your job. Almost 90% of the time, when I start a new group class and I ask, "Why are you learning English?", students will say, "I need English for my job." The more we talk, however, the more it become clear that the student doesn't really use English at work. The student wants to make a good impression by attending classes, by appearing to learn English - but that doesn't mean that the student wants to actually learn English (or, for that matter, do the work that comes with learning English.)
Don't fool yourself. If the only reason that you want to learn English is that you think it'll keep you employed, you're probably better spending that extra 2-3 hours at work.
English will not make you smarter. A good English teacher CAN show you ways to learn more efficiently and to learn in a more efficient manner. That doesn't mean that learning English will help you raise your IQ. Sorry.
English will not make you sexier. Just think of the number of genuinely sexy English-speaking actors and actresses you know. Then think of the number of genuinely sexy actors and actresses (and singers and so on) who don't speak English as a first language. I rest my case!
English will not help you make more money. I have no research to actually back that up; at the same time, I have to say that I don't know of any studies that show that you'll make more money if you speak mediocre English. You've got a better chance of making a better salary if you speak really great English and by that, I mean being able to show that you speak English at the First Certificate Level, or better. That's not a crazy assumption: just look at the number of job adverts that specify a "nivel medio-alto de inglés." (Like I said, I haven't been able to find any research that can prove this. I may start writing people to get more information.)
There's nothing wrong with wanting to improve your English, and being motivated is certainly an important part of that. Just be realistic!