I'm afraid you can't change your own physical gender through magick or medical treatment. However, you don't need to! You can identify male, female or both or neither as you feel it's right for you.
If you think you can do this safely, just ask people to address you as she/he/they the one that you prefer! Being transsexual or genderfluid is totally fine. Don't believe who tells you have a problem, they are the ones who have a problem in being so close minded! If you need some support ask you local or national LGBTA community. If you live in a close minded or violent area remember to put your safety as your number one priority.
If you have some other questions feel free to ask me as I'm a proud member of the queers!
Peace Love and Respect