Is it normal for your eyes to be fine ( good vision) all your life and then in high school discover you need glasses?

Vision changes: Yes. It is normal for your vision (eye muscle function and lens transparency and flexibility) to change throughout life. Some experience changes in late gradeschool, highschool, college, and at any time beyond. It's basically a part of aging. It's just that we can never tell how fast it is going to progress.

Sometimes: Some patients will develop the need for glasses in late puberty due to either mild near-sightedness or manifesting latent far-sightedness.