Inconsiderate person with a disability

The other day I was at Wal-Mart getting my groceries, which is hard for me to do in the first place. I know I look normal, but I'm not. I may not be in a wheelchair or riding in one of those motorized carts at Wal-Mart  but it is a challenge for me also. I was waiting in line to check out when this woman in one of those motorized carts ramed right into me. I looked at her and said oops we collided and I smiled. She just frowned at me like, sense my cart was full and she just had a little that I should let her go first, but I was beginning to wear out too from shopping and I stood waiting in line just like she has to. Was I wrong? Should I have just let her go ahead of me? I am known to let people ahead of me, but I was really hurting and I wanted to get home just like she did. Thanks for listening and giving me your opinions.