It is a shame but we live in a "carry your papers" society. My job won't change my name either on anything until it is legally changed. They have been supportive of my transition so far. I can kind of see it from their perspective though. If someone calls to speak to "Britney" and there is nobody there legally by that name, they might not be able to find me. Since I also work with sensitive and secured data I can't use pseudonymns when dealing with customers either unless it is a nickname variation of my legal name. Plus, for tax and insurance purposes, building security, and a host of other things it could be risky to be going by a name that is not legally mine. As soon as I get it changed legally they are completely happy to change it on all the company files and documents. I suppose school is the same. On the bright side there is no issue with my co-workers verbally calling me by my preferred name despite that it isn't official.
Sometimes I feel that transitioning so far is less medical and more legal. Instead of simply getting hormones and surgeries, I've got to go through therapy just to get letters for the doctors, go to court just to get the name and gender changed, etc. It is a shame in a free society that anyone has to ask approval from anyone to live how they like. I shouldn't need permission to do anything but that is not the reality unfortunately.