Do you have an equal balance of male or female characters in your novel? I have eight characters in my novel, which I believe is fine for historical fantasy. Four are male and four are female. The protaganist is male.
What influenced the sex of your characters?
My main characters in my novels have been female but I do have male characters too. In the books (unpublished) I have written for children, the main characters are mainly boys but that's probably because I worked mostly in schools for boys. I felt I could write more about their antics than those of girls
My MC is female. The story just worked that way. I don't think I've had any problems getting into her head, in fact I've found it easier to write for her than the other characters.
In my YA fantasy my MC is a 15 year old boy. I have female characters, but they are made up from observing the behavior of members of the opposite sex that I know, as well as drawing on my own experiences from when I was younger. So far I have not had any complaints about my portrayal of these characters. Though it is one area that I have asked my wife to pay close attention to.
In my adult sci fi I switch between first person 26 year old male and first person 21 year old female, a challenge, sure but I believe in both of my characters.
I haven't had a problem writing from a 21 year old female first person POV but then no one has read it yet, so although I think she is 'correct' I have yet to be told otherwise.
I think you can write both POV just have to draw on your life experiences in a different way.