Been There Done That...Now What?

Went to a swingers' party last weekend for the first time. Got into some hot BDSM roleplay with an older couple. One minute we're chatting, next thing I know there's ropes and cuffs involved. Pretty sure they enjoyed my submissive streak. Left feeling confused and kinda naughty. Anyone else ever have this happen unexpectedly? Am I just getting old or is this normal for fifty-somethings too?