Everyone should be able to surgically "change their sex" if they want, as long as they have the money to do it.
However, given the high suicide rates trans people have, maybe it would be best to not encourage this behavior, it's a choice for the rest of your life which should not be made on a whim.
Someone will say the high suicidal rates are because of discrimination by society, which i don't agree, i'm sure they face some discrimination, but the biggest cause seems to be mental instability.
At the end of the day, the important thing is being free to make your own choices and face the benefits and consequences.
Just don't force me to use made up pronouns like "xer" or "zi", if you want to be adressed as a she, sure why not, it's basic respect.