I'm gonna say this with absolute honesty.
You don't need to tell him. Don't take it the wrong way, Let me finish.
Be any gender you are and have any orientation that you have, You don't need to show him directly, Live your life as you like it, He has to find that out for himself soon enough, And when he does tell him "I was always like this. You never asked." With absolutely no fear!
This helps with your questioning as well, Cause you don't need a name for your gender or orientation, Just be who you are.
And as for your mom, She definitely knows.