3.23 GPA in First Semester of High School. Do I still have a chance to get into UPenn?

I just got my report card for my first semester of high school, and I got all B’s in everything except Band and my Independent Science Research class. I don’t really have any feasible excuse for doing this poorly, but I still think that I can turn this around in my second semester. I’m in all the Honors classes except Math, but I’m well on my way to getting into the one next year. I’m on student council and I’m about to have all my required work hours. I got a 26 on my practice ACT, so I think I can do well on my future ones. I’ve been dreaming of going to this school since I was 10, but I’ve read that Freshman year with big schools like this can make or break you. Is it all over for me? Or can I still succeed if I get a 3.8 or higher this semester?

You still have chance. If you can turn it around, it will show the upward tread, which is favorable.

Yeah. I’m not sure how many As you would need to get, but you should really bring that GPA up to the 3.8ish range to compete in that pool of applicants. Be wary of making a school your “dream school,” because often the factors that draw you to that school are present at other schools as well. You could be happy at many different schools, but just focus on raising your GPA right now.