Social pressure? I've been offered so much stuff in the past and I've declined them because they didn't interest me. Many people fall into social traps very easily though, I've seen it happen too many times.
While that is a large portion of the cause for people starting at young ages, that is not the case for me. Everything I've done I have wholeheartedly wanted to do it. All the drugs other than weed and alcohol, I have only done once or twice. It is not a common thing for me to do harder drugs. It was only for the experience, not for the long term usage.
Things like MXE and Salvia most likely won't be done by me more than once or twice every 3-5 months. Once I get 16 or so, it will then become more common.
Last night I wanted to see what Salvia was like for my first time, so I got out the glass pipe and mixed a very very minuscule amount in with some catnip (to add base, since salvia is very harsh on the throat)
Due to the small amount, it only really felt like a weed-high. It was a bit more fun though. I ate chocolate lucky charms, texted friends, and played Unturned. Was a good night overall. I'm not planning on doing any more Salvia for a while though.