Costco review: Checking out in 93 f weather

Today (7/27/21) I was shopping at Costco in Timnath, Colorado. I was running errands with my two underage siblings as I had just picked them up from previous arrangements. It was approximately 93 degrees this afternoon, and as both of my parents were at work, I had to bring my siblings inside (considering it was over 100 degrees in our non-air conditioned car). I was going to celebrate my 22nd birthday later in the evening so I had 2 party essentials (tequila and trulys) in my cart. During checkout the lady (around 5'5", light pink curly hair, and glasses) began by questioning if my membership was valid, and did a thorough investigation of my ID (considering I am a shorter woman who looks younger). She then proceeded to interrogate my younger siblings asking if they had our IDs available, even though they were considerably younger, not handling the alcohol, and standing past the register. I explained it was over 90 degrees and I wasn't going to leave my younger siblings in the car. Being executive members, I have been part of the Costco family since I was a child and have been treated with respect. I watched families make Costco trips and have adults buy alcohol, despite children being present, without discrimination. However when I was with my own family, I was treated in an extremely discriminatory manner and treated in a childish manner by my an employee who denied us service. She proceeded to berate me for purchasing alcohol for my"group", but I watched as other families passed through checkout without any accusations of purchasing for a"group". This is my first and last complaint as I will not continue to shop in a discriminatory environment.