One of the many assets, young women have to their attractiveness that an older woman will never have even if she takes care of herself and hits the gym regularly is the youthful glow. I've met many women at my gym who are happy, fit, and put younger girls to shame but there is something missing from them even when their so full of life and that is their glow is gone. You can see it in the fact that the colors on them are dulled out a bit.
Example of Youthful glow
When you see the glow you'll know. It's like a vibrant radiant color coming off the woman's skin and hair that is gone from them as they age. Many people attribute this is the first sign of aging in women.
Most Helpful Guy
Maybe mid 20's depending on experience.3