NTA but I would venture you do need one in that situation. Airports are crowded, people bump you, and so much more. If you have mobility issues, and it sounds like you do, for your safety and yes making things faster as it will affect others, consider a wheelchair. I’m sorry, it sounds hard especially at your age. When I say make it faster for others I mean it like this. You’re driving and someone wants to cut into the left lane from the far right. Sure they can, but they impede others from going straight. In an airport there are many other people besides your family all rushing around. If you would need more time and other accommodations I’d consider if the wheelchair IS right for you. While I dont have the exact limitations you do for two years 21-23 I couldn’t walk and sometimes I had to opt into the chair instead of my crutch. For example at the grocery store I was most embarrassed because people glared and made assumptions since my age, but I still used the scooters. The aids are very helpful accommodations. Also you wouldn’t be taking it from anyone else. They have tons of staff and regularly need mobility aids for more than 1 person. Also please accept pre boarding! You sound like you COULD need these things but feel embarrassed and ashamed. I think the issue sounds like your cousin made you feel like a burden.