It's a strange custom this one. In Britain, we graduate once and only once: from University (College, Polytechnic, whatever,) and then we shrug and get on with working life. Here in the US it's very different. Fiona, at the tender age of 14, has already "graduated" twice, and we're about to do it all again.
At age 5, she "graduated" from Kindergarten, together with a paper mortar board and rolled up "scroll." At age 11 she "graduated" from 5th grade, which heralds the end of elementary school and the start of middle school, although this event was a little more informal: flowery dresses and leis. At 14, she's about to "graduate" from middle school and will enter High School in the Fall. We get to do it all over again four years from now at age 18 when she graduates High School, along with a proper mortar board and diploma. If she makes it to University (College/Polytechnic, whatever,) we'll have what we British consider the "real" graduation.
Phew! Thankfully we didn't have a pre-school graduation like some do, but if you count that, by the time your child gets to age 21 or 22 in the US, they will have "graduated" five times! I mean, really? I have all sorts of conspiracy theories regarding the need and desire to shower praise on children no matter what they do, and I also have another theory, which is that all these events are designed to make working mothers feel even more guilty than they already do. Who has the time to attend and plan for all these things when they have a job to do too?
I also find it hard to keep track of what's required in the US education system, since it's so completely different from what I went through in Britain, and the plethora of schools is just one of the differences. I know that people here have no clue about the education system over in Britain either, and in fact, I've found an incredibly useful tool for those of us living over here, who are trying to explain to our American friends what happens over there: Harry Potter.
Most people have read the books, or at least seen the movies, so they're familiar with the construct. Harry goes to Hogwarts in his first year at age 11, and there are seven total years, meaning kids leave Hogwarts at age 18. Simple enough, right? That's the basis of the British education system (muggle or wizard). Senior school is seven years long, then you go to University (College/Polytechnic, whatever.)
Exams are similarly simple to explain. At Hogwarts, in year five the students take O.W.L. (Ordinary Wizarding Level) exams, then in year seven they take N.E.W.Ts (Nastily Exhausting Wizarding Tests). In Britain, we muggles have "O" (Ordinary) levels in year five and "A" (Advanced) levels in year seven - although I think they're now called GCSE's, (General Certificate of Secondary Education, but the concept is still the same. And there you have it. Amazingly enough, I get a lot of head nodding once I explain it this way. Go figure.
On a related note (well not really, but it's just fun), there's the tough concept of explaining to Americans where you come from in England if you don't actually come from a place everyone knows - like London. If one more person asks me where in London I'm from, my plastered-on smile will begin to severely slide. This is where Game of Thrones is an absolute godsend.
Everyone who watches G.O.T. knows of the rivalry and hatred between the Starks and the Lannisters. Everyone with ears can hear that the accents of the two clans are very different. Everyone who watches the opening credits can see the handy little map showing exactly where Kings Landing is, in the South, versus Winterfell, in the North; and that, my friends, is where I'm from. Yes, if I were in G.O.T. I would be a full-blooded Stark, (or maybe a bastard one, who knows,) living in Winterfell, or even a little further North closer to The Wall. Sadly, I would also be one of the last Starks to be living too, but that's a completely different story.
Anyway, time to prepare for graduation in just over a week. My middle schooler is now a fledgling high school student and I have to figure out all these high school courses and credits and honors classes and sports activities and community service activities and... I'm exhausted. Bring on the OWLs and the NEWTs.