I used to think girl, but our neighbour has a new baby boy with this name (spelled Rohan) and now I think boy because it's the only person I know IRL with this name.
It makes me think of Rowan Mayfair from the Mayfair Witches. I read it in high school and hadn't heard the name since, so I didn't know it was originally a boy name until recently. I've also met a couple of girl Rowans but I've not yet met a boy Rowan.
Re: Rowan-clicky poll
I immediately think of Mr Bean (Rowan Atkinson).
So unless your little girl looks like that, I think it's a terrible choice for a girl