Now many well-maintained 58-year-old people look just like 40 years old, quite young and energetic. Therefore, in this world, 58 years old is not old, but still very young, so if it is properly maintained at ordinary times, 58 years old should still be very young.
On the question of whether you, a 58-year-old woman, belong to the elderly, my understanding is that scientifically speaking, you belong to the elderly only when you are 60. I hope my answer can help you.