My daughters went to school with essentially the same group of kids from K-12. Their school wasn’t small per se, but I think the experience of seeing the same kids all the time for all those years played into both of their desires to go to BIG universities. I practically had to pry them out of the car to tour anything with under 12,000 undergrads.
On one of our big university tours, the guide said, “There are many ways to make a big school feel smaller, but no real way to make a small school feel bigger.” I agree with that observation. As others have said on here, there are ways to find a smaller community at a big school (honors/fellows programs, living-learning communities, sports, clubs, Greek life). The caveat being that the student has to put in the effort to seek out and join these smaller communities. Both my daughters landed at very large universities - my oldest found a smaller community in her major and also by joining Greek life. My younger daughter has joined and an on-campus fitness group, plays intermural sports and is in Greek life. There’s definitely a learning curve, I think, with large universities and new students need to give themselves some grace in settling in and getting their bearings. Parents sometimes lament after a couple of weeks that their student isn’t adjusting, but sometimes it could take a couple of months or even a semester.
My younger daughter can be more of an introvert (or perhaps an “introverted extrovert” is more appropriate) so we had many conversations before she began her freshman year, about putting herself out there. I worried for a minute about her adjusting to a large U environment, but she hasn’t skipped a beat.
Part of me was also concerned that by going to a large university they would miss out on more of a “hands-on” experience with their professors, but that hasn’t been the case. They’ve both been able to make connections with the professors & advisors that they are interested in - as long as they are willing to put forth the effort.
There’s no right or wrong answer - your daughter just needs to figure out what feels right to her.