It is indeed common in kids and adolescents and they many "grow out" of it. I also started having them as a teen, along with spontaneous lucid dreams... these were the experiences that got me into experimenting with it more. It can be the most amazing way to "psychoanalyze" ourselves and tap into our unconscious mind.
Patman - for a few years I kept having pretty nasty nightmares with my deceased mom, and I did not fully understand why, why so stubborn. I figured it out from my lucid dreams, having conscious "conversations" with the character in the dreams. They completely disappeared after a while.
I find it amazing how similar some of these sleep paralysis experiences are for people - the intruders (or "aliens"), for example. OK maybe we should stop discussing details
Anyhow, it's very common to have these after a drinking binge or when quitting, because alcohol normally suppresses REM sleep (the phase where most dreaming occurs) so it comes back as a rebound effect... plus the sleep is usually disturbed and fragmented, so we actually wake up more frequently during the dream stage, and then find ourselves in sleep paralysis. Or the opposite, fall asleep in a way that our brain and body is not in sync.