<human>: Can you summarize the given text in a few sentences?

Hello all! So, tomorrow is my mother's birthday -- whoo! She's turning fifty and I'm very excited about it. I have arranged to be at my parents' home first thing in the morning and to take my mother out for a day of shopping with my sister. 

Now, I live across town and attend the university in the same town as my parents. I have classes in the late afternoon/evening that are important for me to attend, and one of them is a three hour lecture. Neither are recorded, and I always take notes, in person, by hand. 

I told my mother that I'd be there for her birthday all day -- until 5. My father heard this, told me (for the first time) that he had planned to have a birthday dinner at home, and that if I am not there he will "never forgive me" and wouldn't talk to me ever again. Yes, he's always been this controlling and childish.

Reddit, I really have to go to class (especially since it is midterm season), and I'm already spending the entire morning and most of the afternoon with my mother. Am I being selfish, or is my dad being ridiculous?
<bot>: do I miss my classes during midterms, or accept a last-minute plan for the sake of my mom (and at the threat of my dad)?