I don't think it's surname-y but it doesn't necessarily bring to mind the name of a little boy imo (though that little boy will certainly grow up one day...). It's my 69-year-old father's fn so I do love it for that reason. And he goes by
Franklin and not
Frank, which is kind of different because everyone assumes his nn is
Frank at first (which I dislike).
I did know a little boy with the name
Franklin years ago, and we referred to him as Little
Franklin because of my father. lol
Then there's the turtle, but that's a cute association, I think. There was also a
Franklin on the reality show Boy Meets Boy, and he was cute and young. So I think it could fit just about any age, but I just have this certain picture of the name because of my dad. :)