Do I really have to go to church?  I'm going to wear earbuds and occasionally check my phone during a church mass that I am forced to go to even though I am an atheist.
Why do you want to occasionally check your phone?
I just want to know if it's time for me to leave
Even if you don't want to be there, it is not good to wear headphones in the church. It is disrespectful and rude and it will distract people from the sermon.
I don't care if I'm distracting anyone. I'm here because my parents want me here. I hate going to church and this is the only way I can get away with it.
It's not right to disturb other people in church just because you're forced to go there. You should stand up to your parents and should tell that you don't wanna go. It's not ok to be rude to people in this way.