Fair enough, but I've got a four-year-old Finn (to go with a nine-year-old and a two-year-old - they are not called Finn, that would be odd
but just to demonstrate that I am not limited to a four-year-old sample) and I genuinely only know one other Finn, who lives on a different landmass anyway. There are a few Finlay's about, but I've never heard any of them called Finn, so I guess it depends...
I do, however, know two other Kits (my youngest's name) within the teeny, tiny catchment of our London primary school, which encompasses about three streets
.
Anyway, I think people get too hung up on the supposed popularity or otherwise of a name (which is clearly subjective, or area dependent). If you like it, go for it 
and maybe that way we'd have fewer children lumbered with really ugly obscure names or made up monikers