Is OTHER wrong in the post ? POST : First time posting here. The title sounds awful but let me explain.

A little detail about me, from time to time, I like picking up or dropping off people (that I know) on my way to or back from school since I think that It's a nice thing to do, you know, save em a mile of walking or even money (bus rides). I drive a van at the time so, plenty of room. The girl that I picked up is someone I knew since elementary and middle school. My then girlfriend, NOW ex, and I were dating for about a months so I was in that phase where I wanted to impress her by showing her, or in this case, telling her how caring I can be.

The day before this all went down, I asked my girlfriend If she was down to go on a movie date with me, to which she replied with a happy "yes". Fast forward a day and It's around 4pm. I got out of work and was on my way to Walmart. While driving I saw a girl that I knew from Elementary and her family, 3 younger siblings, one looked like she was about 15 years of age, the other two looked no older than 7-8, along with her mother and what I assume to be her bf/brother, walking out of Walmart with heavy baggage. Thought nothing of it, went into Walmart got what I needed and left. Drove back from Walmart, I saw the same girl and her family. Still carrying heavy looking groceries. The kids year old were carrying 2 bag each, looking a little too heavy. The bf/bro had a bag of coals on a should and bunch bags with on the other. Everyone had something to carry. Feeling sorry, I pulled over, waited for the family to reach my van, which I then got out of the van and asked if they'd like a ride home and that I wouldn't mind. They reluctantly agreed. I helped loading their groceries onto my van and asked for their address We were off. The family thanked me after I dropped them off at their house and apologized for the inconvenience, which I didn't mind. I was happy to help.

Later that day, 5:45pm, movie starts at 6:10, I picked up my girlfriend and we were off to the theaters. Wanting to brag to her about how caring of a boyfriend I am. Told her that I saw an old friend from elementary, who happens to be a female, and her family, walking with a heavy load. Offered to give them a ride home. My girlfriend goes silent throughout the whole ride to the theater. Half way through the movie, she silently blew up at me for, and I quote, "Picking up a slutty bitch in the streets and having the balls to tell her about it" That REALLY took me by surprise. Baffled, I said "Wait what? That's what you took from my story? I picked up a FAMILY not just A girl" Kid you not, she replied "Her family's not the problem here. You don't talk to your girlfriend about picking up sluts" I didn't want cause a scene and left with her. I tried explaining to her once more on the way out but she just kept saying the same thing over and over. Eventually I gave up and apologized for picking up a girl, dropped her off at her place and didn't message her that night. AITA here?