AITA for yelling at my dad?

So I (17F) was in Starbucks with my parents waiting for our order to be completed and my father (50sM) started complaining about how slow everything was being done (there were only around 3 employees behind the counter at the time, and only 1 of them were making our drinks). He started talking about how if they worked at his job, they would be fired for standing around. He just kept making rude comments under his breath until we all got our drinks. It wasn’t extremely busy inside, only a couple others waiting for orders like us so it’s not like it was super packed.

I felt somewhat embarrassed because how he was acting, and after we got our drinks I told him that he was being rude. I already knew that he was in a bad mood (because of multiple people cutting him off in our car today, to the point where he physically got out of the car to try and yell at the guy).

I think I’m the asshole because I lashed out at him despite knowing that he hadn’t been in a good mood all day. I understand he’s having a bad day, but I still feel like his comments were extremely unnecessary and he should’ve kept it to himself. For the record, my mom also wasn’t happy with his attitude and thought he was being rude. AITA?