How do people do it?

Be the first to send a text without being scared? How do people start and keep conversations going? I have selective mutism so this whole talking to people both physically and through text is hard, especially if it's someone I want to know more about. There's this guy I've been texting off and on the past few years. Our conversations never go past asking each other how we're doing. I don't know what to say next and I guess he doesn't either. He usually texts me first. But I want to do it first this time. I want to ask him how his day has been. I know he won't be upset about it or, as my mom used to tell me, bite my head off. It's a simple question I know he will answer. It's just a text. It isn't like I'm calling him. I want him to know that I am interested in him but I'm scared and I hate that. How do people do this?

Ps: I was scared to post this but my cats convinced me to just do it lol.