Well I've been attending folk clubs without much let up for well over fifty years now, and the advice I'd give you is as follows.
In the phrase 'folk music' - folk comes first and music second.
There are all kinds of folk clubs - some see them selves as serious curators of the tradition - some are places were anxious parents get there kids ready for going on the X factor next year. And all points in between.

there are places that see themselves burdened with a feeling of superiority. no one talks to you. they can't wait to do their bit. they think their vision of folk music is the one that is the only valid one. steer clear of those places - unless of course this is the sort of place that appeals to you - and you can spend your life sneering away to your hearts content.

In actual fact there are intricacies to be appreciated and things to enjoy in every aspect of folk musoic.

Even if they don't specialise in your favourite form of folk music. I'd say choose a club where they welcome you with a smile, where they are pleasant, polite and encouraging. really we're all on our own and we all need the warmth of friensdship in whatever we're doing.