AITA for refusing to watch someone’s stuff at the airport?

The title really said it all. Someone asked me if I could watch their stuff whilst they’re going to the restroom. I said “I’d rather not. It’s the airport so I’m sorry.” And it’s the truth. But I’m also kinda tired from waking up at 3:30 am for my flight so I’m feeling a bit selfish. She seemed rather annoyed at my response.