Taking a class is terribly inefficient. You tend to learn what the professor wants you to learn rather than what you want to master. By the time you get to apply the knowledge in the workplace, you’ll probably have forgotten some of the details. The class proceeds at a pace the professor chooses, which may well be too fast or slow for you. And unless it’s an online course, your body must be in that classroom at a fixed time, say Tuesdays and Thursdays from 7 to 9pm.
Instead, why not consider a tutor? You learn precisely what you need, at your own pace, with all the feedback you want, at a convenient time in the comfort of your home, and at a cost similar to that of a typical college course.
What can you do today?
Is there something you need to learn that could make you more successful at work? A computer program perhaps? Try contacting the appropriate department at a local college to find someone who can teach it to you one-on-one. Sometimes, even a high school kid can do the job.