(D&D Beyond seems to be having some issues, since I couldn't follow your link to your character or send you a Message. Here is what I was going to send you.)
The rest of the group had been there for 5 years, so it is possible that they held off giving your character the letter as a disciplinary means. You could arrive just outside the Academy or at the Capital that it is attached to. Btw, you were very spot on with your world notes, everything there fits perfectly into the cannon.
(D&D Beyond seems to be having some issues, since I couldn't follow your link to your character or send you a Message. Here is what I was going to send you.)
The rest of the group had been there for 5 years, so it is possible that they held off giving your character the letter as a disciplinary means. You could arrive just outside the Academy or at the Capital that it is attached to. Btw, you were very spot on with your world notes, everything there fits perfectly into the cannon.
We, technically, have enough players to continue our adventure; though I will not turn away those that are still interested and desires to play.