Hello and welcome!
What you fear and think about is very normal. I think we all felt like that at your age, and yes, as you get older, your thinking will change. You'll begin to see that no matter HOW many years go by, and no matter how you may look, you will always feel like the same person. Vanity will not be as important to you as it is now. Some people are more concerned about appearances than others, but at your age, it IS a hard idea to wrap your brain around, getting older.