Probably going to mirror a few answers here but here goes
Quote1. When do you get to legally be the gender you identify as? Do I need bottom surgery to legally be a man? I have no desire for bottom surgery - if I could snap my fingers and have a cis man's junk I would, but as it is, I don't like trans men's surgery options. I do want top surgery though.
This depends on the state/country you live in. I can only attest to the US.
Here is a nice graph showing what's possible in which state "loosely"
http://www.vocativ.com/culture/lgbt/transgender-rights/?page=allI have been informed that NY is getting some more rights for transgenders soon so that state is out of the lineup as far as updates go.
Quote2. How expensive are surgeries? How expensive are hormones? Do any school or work insurances cover at least hormones?
All of this is a wide variety of costs. Hormones can range anywhere from $15 co pays(with insurance) up to over $150(without insurance)
Granted these numbers are literally each end of the spectrum. The average costs for a 10mil bottle of T usually runs persons $50 range (goodrx is a great coupon site for this)
School and work insurance also vary greatly per state and which offer them.
Here is a good list of insurance providers that cover trans* related costs
http://www.hrc.org/resources/entry/finding-insurance-for-transgender-related-healthcareAs far as surgeries go, this also is a massive variant in costs. Top surgery has many procedures and many surgeons charge very different things per each of these.
A very very average number across the board for say a larger chested person would be in the 5-6k range.
Again this is a loose number and not the standard. Good site to start looking at:
http://www.topsurgery.net/costs/Quote3. If I was to get married while I was still legally a girl and then got my gender markers switched, would thst nullify the marriage in some states, or would I just have found a loop hole in the system?
I have been married to a male 8 years now and listed as a female. I too had that concern for when I change my gender marker to M that it would null my marriage but it does not. As far as I can tell all 50 states recognize a marriage between a M & F EVEN if one or both persons later change their gender. The states see the marriage as a contract. The original contract still holds until one or both of the spouses contest it.
Quote4. How does being on T affect your vagina? I've heard people talk about vaginal atrophy which sounds unpleasant.
This varies per person and no one can for sure say what is going to happen to you down there.
Atrophy is a possibility but it is not guaranteed. If it does happen there are medications you can take that do help and alleviate it.
You could also experience clitoral growth as well. No one can say how big nor small it will be nor stay. That's genetics.
Quote5. I'm Hispanic and already have ass hair and back hair as a girl, is getting on T going to turn me into a forest? Will it maybe be easier for me to grow facial hair?
Hair is genetic. If the males in your family are exceptionally hairy then you have a chance of being that way too. But again it's not a guarantee but it is a chance.