To start for anyone that may be concerned by the title, I've always considered myself an ally and I've supported both family and friends when they came out to me. I've always known that it takes a lot of trust for someone to come out like that, and I want to be the friend that they feel safe to talk with about that stuff.
I'm autistic, and I've recently started my journey of understanding that, my gender, and my sexuality. I've suspected since college that I was ace, and finally understood that about myself in the last few months. I made the first public message ever referring to myself as queer in a casual setting as a passing comment today which honestly felt a little strange, but already feels natural.
What I need help with understanding, is why should I actively tell my friends and family about it? The way I see it, I've always been this way and nothing will change in me between now and 10 seconds after I say something. I don't think of it as hiding anything either, I think of it as me being me. Why do others feel the need to share with people close to them?
The point of coming out for the pride movement is to represent for the rest of the community, to let them know they have allies and peers and are not alone. And when hate groups know we are legion, they are cowed and less inclined to harass.
That said, by all means do not come out until you are good and ready and it's safe. Especially if you suspect your food, job and housing might be at risk or your region deals with a lot of hate crime.