Other than calling you pregnant that's a pretty good job IMO. I don't believe you can tell from a grayscale photo if something is red/green like the colours in your shirt, so the fact it took a 50/50 guess and got it wrong with that one item isn't that bad at all.

I saw a documentary about people who re-colourised images professionally and they said that a lot of the decisions on what colour to make clothing was done based on research of what styles, dyes and inks were commonplace in the time period, rather than the photo itself.