Is there an age you judge someone for getting drunk?

So this is what sparked my question:

I was at a big concert last night (45k+ people) and after it was over my friends and I were standing in a line for a shuttle to one of the remote parking lots. For the record our group was in the 33-36yo age range, all women. The line was long by several hundred people, but it was moving at a good pace.

A woman and her friend (both, I am guessing in their mid-late 40s) approached our group, mid-line, and the woman asked if she could cut with us because her friend was drunk. Her tone was of the "you don't mind right, you get it" variety. Her friend was standing but had the obvious dazed look of someone who has had too many. We calmly said "no" and pointed to the very long end of the line saying all of these people have to wait and so do you. She called us bitches and dragged her friend off.

We all rolled our eyes and talked for a moment about how entitled it was, but the one common thought is that a person of her age should know her limits by now. If she wants to get drunk, fine, but don't expect special treatment.

Are we ageist for having a higher standard of a slightly more mature person then say, a 21 year old? Do you make exceptions for younger people who are publicly drunk more then you would for an older person?