18 & pregnant.

I am currently pregnant (5w 3d ) with my boyfriend of 4 years.
I'm enrolled in college and I guess I'm just nervous about telling my family. & I have been feeling really nauseous lately. I told my 3 sisters and they all are very supportive which I am thankful for. I live with my grandma who is always saying how I am such a good lady and don't want to disappoint her.. Any advise on how to tell her or when?
Also any advise on being a first time mommy, comment please! Thanks ❤️