Sadly, you cannot pick your parents. You are stuck with what you have. Just apologize, buy her a card or something. Mom will get over it. Unfortunately your mom behaved like a childish spoiled brat today. But everyone wants to be remembered on their special days, the pain she felt was real but she acted badly and not worthy of an adult. But there is no point in pointing that out. You are a young man, this won’t be the first or last time you have to say “I am sorry” (even if you think you weren’t that wrong). It goes with the territory, get used to it. Learn to say it convincingly, it will serve you well in life. My mom was always sure to remind us of her upcoming birthday and Mother’s Day ahead of time. So this never happened to me when I was growing up. Put your Mom and Dad’s birthdays on your smartphone or computer’s calendar set to repeat yearly and remind you a week before. That will avoid future recurrences.

Throwing things at you? We talking bouncy balls or plates?

If I were there, I would have helped. I'd have thrown things at you, too, you little shit kid! How do you forget Mom's birthday?

Sounds like yesterday was a shitty day for mankind then, the day a complete monster was born.

That’s toxic asf if she’s throwing things at you cause you forgot her birthday

more her fml than yours. apologize and get her a gift to match.