Yes, your eyes are normal at your age to require a stronger prescription annually. Your eyes probably won't change as much in your 20s and 30s; but when you are 40ish, you will probably need bifocals. I am 56 and just recently went to an opthamologist, and my nearsightedness and astigmatism had gotten better, but I need stronger bifocals (or they keep making the print smaller! LOL). I commend you for having annual eye exams. and that you are taking good care of your eyes!