needing to speak up

I've been told I needed to speak up a lot of times because I always kept things to myself. Mostly to my dad and his side of the family. I don't know how to talk to them and I can't trust them enough knowing they will get mad. When he wants me to do something and I don't want to, he responds with "you have to", but I'm old enough to decide what choices I make and what I want to do. That's why I avoid him and when I hit the moment when I learn to speak up is when I'll stop listening to him and do as I want. My mom tries to help me but he won't listen. That's maybe the reason why I have a better relationship with my mom instead of my dad. My dad was really never there for me growing up and I don't usually see him often but he never sees me or my mom until one time every week which caused their break up. So I live with my mom and visit my dad sometimes. My hatred for him is probably from not seeing him often but it also cod be from trauma I don't tell him how I'm feeling or anything I don't start conversation unless it's something with me leaving or not wanting to do something. I don't really like to tell people things in person, I prefer to do it online so I can't see their emotion and how they act as a sensitive and emotional person I am.