I feel like university in the US and the UK are really different, and it depends on how you feel about these things, like, does it sound like what you want from higher education?
In the UK, you will focus on one, sometimes two, subjects and not really go outside of this subject very much. For example, if you are doing a maths degree, you only really do maths for those three years. I'd personally find this to be a perk, but if you aren't sure what you want to study, probably not. The drinking age in the UK is 18, so alcohol is more central to student life from the first year. Studying in the UK seems to be a lot more independent than the US as well. There is much less emphasis on sports in the UK, generally (with the exception of things like the boat races).
Which unis are you considering? Bigger universities and bigger cities will give you a different experience to smaller universities.
Did your parents come along with you to the universities? Also, did you get chance to visit some of the cities where you might be studying? That could help convince them.