There are parts of the game that make it seem like you are relative Johnny-Come-Latelies to Brindlewood Bay. Other parts of the game (e.g., questions to pose to the players) imply one/some of you have been here most of your life.
And we know the Murder Mavens have been meeting (in some form, of some membership) for a decade, though that might be as much a function of “I’m widowed now, what to do, what to do” as time spent in BB.
The actual answers, to the extent they are meaningful (again, we’re not writing James Michener novel here) are likely all over the board.
My take is – it’s probably best if you have some info about the town (you’ve been here a while), but are not so steeped in it as a permanent resident. Maybe that means being born in BB, moving away as a child, and returning post-spouse, post-career? Or maybe you moved back here sooner than that. Or maybe you grew up elsewhere but had family here that you sometimes visited. Or you lived in Boston, but came up to BB and its environs on vacation. Maybe your husband had roots here. Maybe you were from Faversham, not too far away, so BB was in the backdrop of your experience, but not your actual life.
Give a little (please, not too much) thought to that question as you think up your Maven’s backstory.
(As a side note, Jessica Fletcher and her husband Frank moved to Cabot Cove as a retiree about a decade before MSW begins, Frank passing away shortly after they do. There’s some indication that Frank had roots in the community, perhaps as a child. Not surprisingly the show did not create a tight continuity for her past. More info here.)
(On a completely different tangent … are the present members of the Murder Mavens the founders? Did some join later? At present there are just you three – have there been others at times? Why are they not around any more?)