You ought to be concerned for the correctness or incorrectness of your pronunciation at all times. You do not want to become a deep-seated person in your mispronunciation. It is a lot easier to learn something correctly than to correct a bad habit. This is not to say that you won't make grammar or verbal mistakes. In fact you will make mistakes.
Human beings learn through analysis, trial and error, correction, and constant practice.
You may select the easiest word for you until you get acquainted with some other words. A notebook of your preference to keep all your notes organized and in one place. Be sure to date them. When time passes, I encourage you to check your old notes and see how far you have come. A book with colored pictures is relevant where subjects and points are well defined in each chapter.