I believe Lily is not legally a woman yet - Lily would have to marry as a man by law- being born male and not having a GRC. Thus it would be a dull straightforward heterosexual marriage with a woman, and thus no fun at all, and not remotely special.
You see, self ID is not actually law yet, despite numerous organisations, political parties, councils etc acting as though it is.
Lily is not legally a woman until Lily gets a GRC - Lily has previously claimed on twitter to have a GRC, but that is clearly bollocks given: Lily's age, Lily's first GIC appointment only being a matter of months ago, and Lily bemoaning the fact that Lily could not get the sex on Lily's passport changed.