Today I had a lot of fun with a group of mums and kids in a muddy obstacle race. I fell into the muddy pool while my mouth was opened and drank some muddy water by accident. Then I said to the other mum I better "keep my mouth shut" as I didn't want to drink anymore muddy water. The instructor then said I was rude by saying that.

Is it very rude and impolite to say that in that situation please?