Good points by posters above. This time commitment question is a great question to ask ROTC participants during an on-site visit in your final short-list of schools and I'd ask how that changes per year, as it sometimes does. Also if Navy, explore Navy option vs Marine option time commitments - Marines may be on an overnight weekend march, not so much for Navy option.
But as you stated , it varies per school and military branch. For example, there are schools in which the ROTC participants will be attending every home football game, working as security, or spending hours cleaning the stadium after the games. also may be spending hours clearing snow from parking lots or the stadium in colder climates every time it snows. Also, does your unit do community outreach, color guard, recruiting events, etc. ? and if your child opts to advance in leadership there will be additional responsibilities in higher years as you advance to a work supervisor, unit lead, brigade leader etc.
One other point - time commitments have so greatly changed during covid - I don't know when and how fully they will come back. so vet that out, too.
Some events, like nights in, are fun but also take time.
Bottom line even with those details is that time management is just necessary
but I agree with other posters that it's surmountable if one is focused, not overextending outside of ROTC, etc. I think a lot of our young adult children are finding time to have a fun 4 years in addition to their schoolwork and ROTC training. If your DD is interested to serve then I think learning to manage time through ROTC participation and college is a great opportunity. Honestly I've seen a maturity in my DS and his classmates already in their first couple of years in training- Pretty great group of young people *well most of them but those who were a little not fit for the program are getting weeded out
Honestly others look to the education cost but to me the main benefit of ROTC vs OCS path, IMO is 4 years of this pressure and experiences shapes these young leaders. Good luck to your DD and thanks for her willingness to serve. good luck!