Well, that's my age bracket.... and a fair few other people on this forum! I definitely don't slag off teenagers, indeed q the opposite and I definitely don't think that rude people fall into a certain age range or gender.
Re the rest of your post, I honestly don't understand what you're saying. Did you not invade the woman's personal space and privacy due to 'wedging' yourself in when the couple who let you through didn't move??? Maybe I've misunderstood, but, as it's written it sounds like you were the one being rude!
TBH, I don't think anybody was being particularly rude, but I have come across a lot of older people who feel they can say and do as they like by virtue of age and/or experience. I feel as I get older that I don't bend as much as I did when I was younger to please others, that might be considered rude, but I just want to be honest.