Would it be okay if I decided to skep an expensive outing with my girlfriend's mom?
What's the relationship like between you and your girlfriend?
My girlfriend is my best friend
It is wrong to skip events with people after you have made plans. She might think you are being weird or shady you should tell her the truth.
I should confront her and tell her I'm doing an interesting activity.
If this is something you already committed too then you shouldn't skip out on the event. If something is bothering you about it, you should discuss it with your girlfriend.