It makes sense to me, hon. And to me, crossdressing is just one form of expressing your gender identity. You are one of us.

Not every MtF needs to be ultrafemme. Some are happier that way; some are not. It just depends on the seriousness of the dysphoria.
So you have memorialized your sister already, by telling us her name.
There is a famous meditation by the medieval English author, John Donne. Is states:
No man is an Iland, intire of it selfe; every man is a peece of the Continent, a part of the maine; if a Clod bee washed away by the Sea, Europe is the lesse, as well as if a Promontorie were, as well as if a Mannor of thy friends or of thine owne were; any mans death diminishes me, because I am involved in Mankinde; And therefore never send to know for whom the bell tolls; It tolls for thee.Every persons death diminishes me because I am a part of mankind. I lost a sister, in Brigid, I never knew I had. Yes, she was brave to take on transition. It hurts when I read in these pages how many families do not accept their trans children. I have four kids myself. I cherish each and every one. To break up the family would kill me.
She was fortunate to have you. You should not feel bad about things that might have been said. All siblings argue and squabble. Something would be wrong if the didn't! Can you tell me more about her? What sorts of things she she enjoy in her life?