I lied to a homeless person

When I was 14 years old, my mom and I went to the grocery store. I was bored so I went to wander down the aisles looking for snacks, and I came across a homeless man that was pushing a cart and wearing tattered clothing, asking people for spare change. I was 14, I was ignorant, and I decided that I wanted to prank him and see if I could get a reaction out of him. So I walked up to him and asked him if I could buy his cart from him, and he told me I could. I then asked him how much it was and he said “3 dollars”. I then pulled out 3 one dollar bills and gave them to him, and said that’s all I had. He then let me take his cart. He had been carrying all of his belongings in that cart, and he was left with nothing. He was left standing in the middle of the grocery store, looking like a fool. I then asked him for a picture, so he would let me take a picture with him. He said okay, and he then put his arms around me and I took a picture of us, with him smiling, and me smiling back at him, as if I had just won the lottery. I then walked away and left him standing there, with nothing but the clothes on his back. I felt so ashamed about what I had done that I never told anyone about it, and I’ve kept that secret to myself for over 10 years now.