on my first day oif school, I noticed that there's this one person who had all of my first four classes (lunch, fundementals of science, world history MG, english MG,) and that we both went for the same clubs. the really freaky thing is, when trying out for drama, we got all the opposite parts of a dialogue. I was person A, she was person B at a different time but same play... to further the coincidence, we both have more than 3/4 of our bloodlines from the british isles, and to top it off, we're both pagans!!! I find that to be a very improbable series of coincidences.
That's pretty cool. It's weird, but it would be awesome if that coincidence turned into something really cool between you.
The winner of every presidential race in history (in the US) was the one with the most genetic ties to European royalty. I shit you not. You statement about the British Isles reminded me of this.
Things like this are probably much more common in smaller schools. There aren't so many classes and clubs to pick from, so you end up seeing the same people over and over again. The people who are interested in taking algebra, for example, are likely to be the same ones who take biology. There might be only one section of the class, so they will end up in classes together.