You will learn to say NO.
You will learn that someone asking and you having the ability doesn't mean you should automatically say yes.
Learn to say "I'll let you know." "Let me check my schedule." or be honest and say "I have too much going on right now and can't do it."
This week, you will say NO to someone who isn't family.
So they get pissed off.
So they get offended.
They'll get over it.
You let yourself become the go to girl.
They'll keep asking until you start saying no.
Visit your MIL and help her wipe bloody drool from her chin or go help self-absorbed people pull off a birthday party when they already have plenty of help?
Have any of them even bothered to go see her?
She matters in your life.
They don't even rank in the top 10.
Let them deal with it.