Providing your mother with information on social anxiety is a good idea. Also, speak to her about it when she's in a good mood and don't be too pushy about it - show her you're serious.

I 100% understand your problem. I have Anticipation Anxiety and my mother always tells me I don't require help because I'll just "get over it". The only reason I receive help from a psychologist now is because I started having panic attacks at school and the school nurse made my mother take me to a doctor. Of course, I'm sure nothing severe will happen to you for your mother to understand your thoughts, but I definitely understand your problem. Good Luck!