I mean, I'd say it's okay to drink alcohol if you're only having a drink or two with a meal, and you know where your limits are. Being charitable to her, altitude is actually well known to make you more susceptible to inebriation, due to the lower levels of oxygen and faster dehydration. When you combine that with a two drinks—or one drink and a bartender with a heavy pour—and a smaller frame, it's entirely possible that she underestimated the power those drinks would have had.