Transgender preacher

Gender is actually a societal construct. Sure, biologists can divide most species into male and female due to the structure of the body, but gender is a cultural thing. Before colonialism, many Native American tribes recognized up to seven genders. There's a tribe in Sumatra, Indonesia that recognizes five. Now, most modern-day post-globalization people can only conceive of those genders as combinations or variants of two.

With Wicca (correct me if I'm wrong) the gender binary essentialism is a cornerstone of the fertility-based religion. (Although Christopher Penczak among others has written about Wicca's empowerment of gay and queer people, unlike some world religions that condemn anything outside the gender binary.)

Going back to the Bissu of Sumatra, to be transgender isn't only "something that has come up" but seems to be a requirement to becoming a spiritual authority. In the Western world, I can only think of the Greek legend of Tiresias who became a spiritual consultant after being "cursed" with a gender swap (and blindness, I think--? Blind seers were an irony that Greek dramatists just loved,) and of Odin learning seithwork (in a culture during a time that, to my knowledge, actively forbade men from learning that craft.)

You kinda dodged the question

Aeon was only giving you information and history of the subject (i assume) to help you find your own answers.

Sexuality and gender roles arent limited to non-wiccan societies. I believe the choice to be a priest or priestess is up to the discretion of the coven the transgender/sexual. Personally, nature comes in all shapes, sizes, genders and "blurred" genders. So why would the practice of magic and roles be limited...nature itself isnt.

Like Aeon said, gender roles is society thing...

There is no overall single answer to the question. Wiccan covens are autonomous, so how a coven views the place of transgender within the coven is entirely up to that one group. I know some covens who would treat the individual according to their gender of choice and others who would insist on treating them by their birth gender.

Since I'm assigned female but I'm male, I would not be a priestess or any position for women.

I've been described to that each of us have the divine masculine and divine feminine energies within, so the physically recognized gender doesn't matter as much. I can't speak from a traditional viewpoint, however, but the issues that involve transgendered folk in Wicca are not new.

It depends. If you're solitary it doesn't matter. If you're in a coven, bring it up with them. Some go with the chosen gender, others birth gender, and some go with gender until you have the full surgery because physically you would be male or female. It really depends. Personally it's what you identify as. I have a female covenmate who was acting priest for about a year because she was a good leader and we joking said she had more masculine energy than any of our male members. I feel the key is connection more than actual gender, but different covens different rules.

It really doesnt matter its just a label.

If it were me in the situation, I'd probably want to act as my identified gender (not birth gender).

Since we both have feminine and masculine energy it seems to me it would be most appropriate to act in accordance with the one they identify most with as I assume they would be more drawn to the energy of that gender despite their birth gender.

But, as others have said, it's going to depend on the coven. Or they could always start their own!

It matters a very great deal in certain covens and Traditions. It is by no means "just a label". It defines the person's relationship to the God or Goddess, the channeling of specific energies, and a representation of the Sacred Marriage which is central to Wiccan belief and practice.