I started on Guitar with folk (having played Jazz on clarinet and sax)then got into Banjo when working with another guitarist. It seemed a natural progression to move to Mandolin as well, and has not been a problem for me,except that I do like a fairly wide neck on Mandolin (and Banjo if it comes to it) as I have fairly wide finger ends. The main advantage was that having to use a flatpick on the Mandolin I can now do a basic flatpick on Guitar as well. Goog luck any way and HAVE FUN.