Not sure if it's relevant but got taken to the Caves of Drach on holiday when fairly young. Don't remember it, maybe it was a subconscious starting point?
Anyway, what I see as the seed sown, much later, on a DofE walk from Newby to Stainforth via Giggleswick Scar, as curious teens that we were, popped into a few of the obvious caves enroute. It was a few years later that a school friend and I returned a few times (when we could drive), camping at Langcliffe and Stainforth that we retraced our younger steps and looked at maps and found more caves in the area. A spot of mountain biking near Clapham saw us spotting Ingleborough Cave, which then led to the Gaping Gill winch, which ultimately led to joining a club..