It's bizarre how that's a thing. I'm in year 13 and I've heard people "showing off" of sorts about losing their virginity since year 10-- they were WAY too young at 15/16 back then.
I guess it really is just a way of initiation. At least if you get a STD, you have proof, because it was "worth it just for fun" without getting tested beforehand.
It really should be something more special, such as doing it with someone you genuinely like (or at least for the first time).
From what I've gathered, I'm pretty much the only virgin left in the year (about 75 of us) and that's by choice-- mainly because I'm a lesbian who hasn't come out yet, but that's a whole different story!!! XD