Those are not out kids! One of them is a Landgrabb. In addition to a wide range of kids from different neighborhoods, I saw two of the three sages from Realm og Magic, as well as a couple other familiar faces from different neighborhoods. OK, I can see Eliza Pancakes becoming a student. Maybe the kids belong to other students there, I do have a story progression mod (MCCC) that lets adults and young adults marry and have kids. Or maybe the game is just weird.
Now for the important part: GRETTA IS NOT GOING TO LIVE ON CAMPUS. Seriously, the Sims 4 design for Uni and ageing is the worst possible if you care about your sims.
Not only do you age on campus. I guess that is realistic, although in Sims 2 I justified the extra inserted "Young Adult" age because in real life, people with tertiary education actually, physically, statistically live longer by several years (on average, obviously. Look before you cross the street.) Still, you can fix this with an elixir, either from the Reaml of Magic game pack or from the reward shop if you live a reasonably fulfilling life. (Like taking the Academic career before you go to Uni.) But EVERYONE ELSE AGES TOO. Including family members you have no control of. They achieve nothing, they just grow older.
Also, you move out for real. In Sims 3 you would go home after each semester to your waiting house, and everything would be as it was when you left. Now, you move out as if you were starting a new family, dividing the family funds. (You still have to pay the bills for your old house, I think? Or is there a bill for the dorms of similar size that your sim pays alone? Probably the first. Maybe it is because I have a mod that pays the bills automatically when they are delivered. Or maybe the repo man would have come if I hadn't given the student enough funds.)
When the first semester was over, I moved back manually and merged the families again. Not only had her brother aged as much as she (without doing anything else, it seemed) but all the potions were gone from around the house. The furniture is still there. The dirty dishes are still there. But potions, some of them rare and life-changing, were all gone.
Don't send your young adult to university unless you are finished with the rest of the family and are starting a new chapter in the generational saga. Which is a perfectly OK thing to do, don't get me wrong. As long as there is a big warning filling most of the screen saying:
"YOU ARE NOW ABOUT TO ABANDON THE REST OF THE FAMILY. THEY WILL ACCOMPLISH NOTHING EXCEPT AGEING FOR THE DURATION OF YOUR STUDIES AND THERE IS NOTHING YOU CAN DO ABOUT IT. ELDER SIMS MAY DIE WHILE YOU ARE GONE. ARE YOU SURE YOU WANT TO DO THIS?"
I think that is a pretty steep price to pay for hanging out in a dorm with the cool kids, especially since it will take at least 3 semesters, each one week long, to complete a single degree, without any electives. With normal lfiespan that is longer than the sum of toddlerhood and childhood. So your literal baby brother could be a teen when you graduate, if you move through Uni as fast as you can. A sibling that is near the end of childhood would be fully grown (but probably not gainfully employed, since nothing happens in your absence). (Teen years last 14 days on normal lifespan.) Adult parents may have died from old age: Normal elder lifespan is 10 days. Maybe this is the future of higher education, but I for one can wait.
University is a great start for a sim fresh out of CAS (although I am not sure the career boost is worth the lost years). But this is not the story I want to tell.
More about University later, if my own Creator allows. (I have a novel to finish as well - it is November again.)