AITA for calling my girlfriend a jerk for refusing to let a couple take priority seating on our flight?

I (29m) met my girlfriend (29f) 2 years ago. I knew her as the sweet girl next door - friendly to everyone, always has a smile on her face. <br><br>My girlfriend and I are flying back from vacation. I’m 6’4 and my girlfriend is 5’10 so as you can imagine, I hate being squished. We found incredibly cheap business/first class tickets (I think it’s called premium economy? We got more leg space and slightly larger seats) so we splurged on those. <br><br>I’m not a rich guy, so I don’t usually get to travel like this, but as previously mentioned, the tickets were quite cheap. <br><br>We get on the flight, and as we are walking down the aisle, there is an elderly couple in their 70s probably. The husband has a cane, and the wife is helping him walk. <br><br>The husband is stopping at each row to break and catch his breath. Eventually, they stop at our row, and the flight attendant says that the husband is in seat D and the wife is in seat C, and that I’m in seat A and my girlfriend is in seat B. We scooch over so they can get in. <br><br>The wife immediately apologizes to us and says that she picked the wrong seats, and hoped that we would help. She said her husband has a bad back and knees, and that she has arthritis in her hips. The flight is 8 hours long, and they have to get more leg room. They noticed that we are both young, and that first class is much more spacious. <br><br>My girlfriend immediately gets mad and says that we specifically bought those seats for a reason. The wife offers to switch with one of us if we don’t mind sitting next to her husband. I was happy to switch, but my girlfriend told me no and said that we were upgrading for a reason, and that it was rude to accept their offer. <br><br>The wife asked my girlfriend to please reconsider. She said they were old and that their bodies couldn’t take the strain of sitting in cramped seats. My girlfriend said no again, and I told her to reconsider. <br><br>The wife then offered to switch with both of us and give us their seats, and my girlfriend finally said yes. <br><br>The couple thanked us profusely and switched seats. <br><br>When we sat down, the wife was crying and thanked us again. My girlfriend was quiet the whole time. I asked her if she was okay and she said she wasn’t. She told me that she was shocked I supported the couple and said that I made her look like a bitch. I told her that she did that herself by being inconsiderate. <br><br>She told me to stop and said that I was being sexist and making her seem like the bad person when in reality I was the one who was being a jerk. I told her no, that she was the one being inconsiderate. <br><br>She has been quiet ever since. <br><br>Was I an asshole for supporting the couple?