Going straight into uni after finishing high school doesn't work for everyone. One of the biggest mistakes I ever made was to go straight into a degree. I'm now trying to complete it to get it out of the way and justify the expense but I've certainly not enjoyed the course. It's probably a bit better in the US with the flexibility that comes with a credit based system and the ability to change your major if need be.
In the British system you typically study a narrow course. I asked about transferring from mechanical engineering to either civil or environmental but was told I'd have to start from the very beginning despite the first year course material being almost exactly the same between them. I screwed up my 2nd year of study and was forced into a year out. I'm back to finish off a course I seriously don't enjoy and I have no idea what I'll do when I graduate
Short version (minus sob story): Think carefully about what you choose to study, if you're not sure, take your time, go work and see what else is out there first.