This is a question for FTM and MTF who are on the path of at least some amount of gender transition that would be evident to another person who has known you since childhood.
During and after transition, we tend to lose some friends and gain other friends. Some relationships get worse, but some other relationships improve. Some friends stay with us, whether we transition or not.
Who is your best friend as of today? How did you first meet this friend? How long ago was it? What makes this person, in your opinion, your best friend? Has this person seen you in both genders? If you have had to come out to this friend, how did he/she react?