I know two 40-something Australian women called
Robyn but in the
UK Robin is very much a male name and
Robyn seems rare for either sex.
I don't know any small boys called
Robin - I think it faded after about 1970, so with that fact in mind I'd suggest that the time is ripe for it to be appropriated for girls, with the nature theme stressed.
It would be a good addition to
Holly,
Ivy, etc for a winter/Christmas baby in the northern hemisphere too.
I certainly prefer it to
Robyn, which seems to be a desperate attempt to feminise
Robin as a form of
Robert and of course takes the name away from any pretence at a "nature" theme.