...I think that having the black belt is another beginning of Aikido...
honto desu! if you look at your friends' rank certificate, the kanji for 'sho' in shodan is the same as in shoshinsha. i think the idea of black belt in the west is different than in the east. that's the first thing someoene asks if they hear you studio martial arts...'oh! are you a black belt master?' blah blah blah.
as shodan, we're starting to get a grasp of the basics, to omoimasu