Is it wrong or immature to argue with one's parents? Especially as an adult child?

As a 29 year old, I feel silly arguing with my mother but…. she’s wrong!

Here’s the latest incident:

My mother, still getting over a bad flu, ate out of the communal sauce bowl at the dinner table with her spoon (effectively, a “double dip”), compromising the bowl for everyone else at the table. When I got upset about it (I need sauce for that meal), she accused me of being childish and squeamish… and then I got really mad. I accused her of being the child for not being courteous towards the rest of the people at the table.

I feel really stupid about getting mad and yelling, but how do deal with a stubborn parent? Especially one who constantly relies on the old “I’m your mother, so I must be right” line?