Changing differences: there's an oxymoron if we ever heard one! But differences are important and enriching for relationships. A younger man can open your eyes to different opinions, visions, pursuits, and can be a real breath of fresh air. And this works both ways: he can also learn from your widsom and experience, so you both teach each other and discover new things.
Physically, a mature woman today is totally different from a mature woman of the same age 20 years ago, with or without cosmetic help! Just look at Sharon Stone, Demi Moore, Madonna and Elle MacPherson: they seem to get younger instead of older. Men really struggle to guess the age of youthful and sprightly women - when you look good for your age, who's going to be bothered about an age gap?!