Hello and welcome! I'm a bit new here, too, and have just self-diagnosed as Aspie.
In response to your questions, I would like to say what I would have liked from my parents when I was small. You are quite lucky that you have been able to get any diagnosis at all, I have struggled with my traits for nearly 30 years before I found this site. In all honesty, the very best thing you can do now, and for the rest of your life with your son, is love him. He, and you, will know hardships and joy that nobody else on this planet could concieve of.
It will be hard, but try your best to be patient with each other. Say what you mean, and mean what you say. I cannot stress this enough. Consistency and dependable routine is a safe haven from the hurricane outside your door. Don't let him doubt himself, and trust yourself and your judgement above all others. You and you alone are his mother, as such, you are his shelter and defender in the world. Let him light the world with what he CAN do, not drown in the shadow of what he cannot do. This is what I wish I could have said to my father. Instead, I endured endless fear, shame, rage, and two suicide attempts before age 25 because I could not be what everyone else wanted. I am only now beginning to understand my own soul, and begin the path to peace with myself as I am, and will always be. Brightest joy and hope to you both.