AIO? My Mom and older brother did something that really upset me but they say I’m being irrational about it

So this isn’t a long post but I wanted to know if you guys think I’m being irrational. I (17 f) finally got to sit down with my mom for the first time in a while. I’m constantly busy with high school, college classes, and my part-time jobs, so I don’t get much free time. I’d been really wanting to show my mom this indie musical that’s currently pretty popular because I’ve been really into it lately. I’d already shown her about half of it last week but we were interrupted so I wanted to show her the rest. I had just paused the songs to grab a charger because my battery was almost dead. My brother (22) came into the room and sat down where I had been sitting, next to my mom and started showing her TikToks. I protested that I was currently doing stuff with her but he just ignored me and my mom didn’t say anything and kept watching the videos with her. I got really upset and told her that this was why I felt like my older brother was the favorite child and that I was the least favorite (my mom always claims that she has no favorite and that she loves all of us equally). Her and my brother laughed it off, realized I was actually upset, and told me that I was just being a “teenager” and that I shouldn’t be so irrational. I never yelled or started a true fight but I shut myself in my room and gave them the silent treatment for the rest of the day. So am I overreacting or am I justified?