Its really just the tonality/timbre of your voice that tells if your a tenor. The fact that you can sing that low in the classical world probably would take you out of running for being a tenor, but it really doesnt matter in anything but classical music.
The size of the adams apple is usually indicative of how deep someons voice is going to be, but not always.Ive seen people with huge adams apples that have Michal Jackson like voices. Yes, the adams apple itself grows but it does in everyone, and its just the size of the corRAB themselves that cause the lowering as you get older.
Its cool that you can hit a soprano C, but if there is a lot of tension you might want to not be doing it so much until you can train properly to get it. You might want to check into getting Jaime Vendera's Raise Your Voice 2; the technique in there would be perfect because if you can hit a Soprano C now and above,you can probably go much higher and it will become more comfortable too.