Maria,

Listen to the people who look at you every day! They’re probably right. So many women have been blond for years that it’s just what they’re used to seeing on themselves, but it doesn’t work anymore. We can’t do the beach thing these days but we sure can do elegant.
After years of blond, the hair starts to look like a helmet where every strand is exactly the same color and the whole head is processed looking. Blonde is overdone and overrated most of the time (though of course, on some women, it’s perfect and the color they wear best. Catherine DeNeuve and Grace Kelly were great elegant blondes).
Light brown with highlights sounds way more INTERESTING than straight blond. You can always change it back. To a one, every single woman I know who got rid of the years of blondeness looked chic and classy. Some couldn’t get used to the difference and didn’t believe everyone who told them how much better they looked and went back to being blonde. They didn’t look better but they felt better and that’s fine too.