I was accepted to an Ivy and top tier LAC, as well. I chose the LAC, just graduated, and absolutely LOVED it! No regrets about my decision whatsoever.
For me personally, I preferred the smaller classes, broader, and more interdisciplinary education that I felt I could get at the LAC. I proudly tell people that I don't have a single friend who is premed and almost none of my friends are in STEM. LACs allow you to interact and work with people coming from so many perspectives, which I LOVE.
Not saying you can't get that at Penn, but in my view, large research universities tend to restrict you more to your major and to interacting with people on a similar path to you. There's nothing wrong with that and of course you can meet friends anywhere - this is just part of how I made the decision myself.
I went to a prestigious high school and was really sick of everyone being cutthroat and obsessed with big name colleges. I felt that the culture of the LAC I went to was way more collaborative and relaxed than it would've been at the Ivy I was accepted to (not Penn).
I also wanted to go to a school with a strong campus culture that wasn't in a big city so students were forced to spend more time with each other and at campus events. This was a major factor for me and I am so glad I chose the smaller school because there was so much to do on campus and events were always well attended.
Again, I don't know much about what Penn is like and the Ivy I was accepted to is probably very different. Just providing my reasons to hopefully give you some insight!
You really can't go wrong with any of these three! Congrats!