I've become quite familiar with the UK education. There's this misconception that in the US you can't specialize in a subject earlier on in your degree, and that's not true. There are gen eds that we're required to complete and most people don't declare their major until their sophomore year, but that's because in order to declare your major you have to meet the major requirements. For example, I'm an applied math major with a minor in physics. I was admitted to my university in the college of science because like most students I did not enter university undecided. I was not able to officially declare my major or my minor until I passed several classes in my major and minor. I was still taking 4 math classes and 1 physics class, but I could not officially declare my major. For the college of engineering at my university, they have to pass certain classes too, but they also have to maintain a higher gpa than my program or they have to pick a different major. So in the US, we do specialize early on but while we are taking classes in our majors and minors we also have mandatory gen eds and it's not official until you've proven you can handle it. I was fortunate enough to take a lot of university-level classes in high school that transferred over, but some students are stuck taking the max amount of credits to graduate on time, especially if they double major. When I'm referring to course load, I'm referring to the fact that we often cannot focus on just one or two subjects because if we did it would take 6+ years to graduate because of all the graduation requirements and if you drop below full-time you lose your government aid.
I'm not saying one system is better than the other. I was saying if Ruby is not the type of person who can handle a heavy course load, as in multiple courses with their own graded assignments every week that can tank your gpa, she would not have made it out of undergrad here.
Additionally, at the master's level in the US, there aren't any gen eds. They are there to specialize in one field. The only difference is that they require more courses in the subject area that you're studying in the US.