I really need some help, or just words of encouragement I guess...

I posted a picture of my sona, Celeste, as a chibi on instagram a few hours ago. Soon after, I got a few comments on there tagging another suiter who has a character very similar to mine, and she's rather upset about it. I just wrote back and explained to her that I've had my character a long time (3 years now) and that I didn't steal her design. It just so happens that they have similar patterns, wings, and the exact same colors (besides black).

I guess it just makes me upset that she assumes I stole her design when I've actually had this character for over 3 years.

So... help, anyone? What do I do if she doesn't believe me? :/