AITAH for how I am defending my kid siblings

I have twin 8 year old siblings. They’re foster care kids and I love them so much. Helped my parents raise them and when my dad passed I kept taking care of them. We are working on getting them to think of me less of another parental figure and more of their brother. Until then I do defend them a bunch while we are out together, which leads me to the next piece of background…

We live in a neighborhood with mostly older people. I have told the twins to stay out of peoples yards but they are kids and they forgot rules occasionally as they learn them. They ran through an old man’s yard and he accused them of knocking shingles off his roof. He walked up to the twins without me there and questioned them about it. I then confronted him about it and got in his face a bit about talking to my kid siblings. I’ve been on edge since.

That leads me to today. Two different girls in the neighborhood came by and yelled at the twins. I didn’t catch them the first time they said something but it made my younger brother cry. When they came around again I asked them to leave the kids alone to which they said that the kids yelled at them first.

I told them to just leave the kids alone to which they went and got their parents and started pointing at me. I went over and talked to the parents and apologized for being harsh to the girls(which I felt like I had been upon reflection). I explained that I was feeling on edge to the old man who now stared down the kids whenever they’re outside and they accepted and we went on with our evenings.

Did I over react? Was I the asshole for defending my kids like I did?