Hi Addie.
You can't change gender in game.
I think you can though, if you ask Support. But, I do remember someone actually changing gender, I can't remember their name though, unfortunately. It was a long time ago, plus cannot remember what they had to do or if they had to pay. I know, I'm not much help but it was quite a long time ago. At least I replied though eh. :
Maybe, if someone else reads this they can shed some more light on the subject.
They might have just started a new account. But, my advice is just ask support about it, they'll get back to you, hopefully.
If you do. Could you post here again if you get a reply please.