Look at Audrey Hepburn. She made a symbol of her brows. Same as Cara Delevingne. I have a thick eyebrows too and they are the best thing on my face. I don`t even need to put any eyeshadow or anything on them to make them look good.
The person who tell you this has no idea of fashion, your eyebrows are very similar than Cara Delevigne's ones who is one of the most famous models now!! :)
I've got thick eyebrows too but I don't give a damn about what they say. It's just something not everyone has. And you should be proud of it. Stay yourself, no matter what xx