Male or female protaganist. Does it really matter?

Hello there, complete newbie here, at your service.

I have recently started to write again for the first time since...well school.

I've had the inspiration, can picture most of the characters in my head, have a very rough plot and have got a few thousand words down.

Thing is I've been doing some reading around and it seems the old saying of 'Girls will read male protagonists but Boys won't read female ones' is still circling around.

I'm doing this for fun at the moment but I would like to dream that I could one day be published.

Do you think having a female protagonist is a turn off for publishers (from a marketing perspective) or would Henrietta Potter have sold just as well?

I'm don't intend to ditch my heroine but I wanted to know others opinions on this.

Thanks,

A.G.Haunton

(P.S. I've recently shared a little snippet of my work, a children's fantasy book, so any feedback on how to be less rusty would be really appreciated.)