Like Matcha said, it's illegal to sign someone up to therapy without their consent in most countries. So you're under no obligation to go.
I'm more worried about your mother gathering a bunch of friends/relatives, misinforming them about the context and staging an 'intervention'. Or if she's truly off her rockers she just does so herself.
Anyways, stay safe. If you aren't doing so already, might want to move somewhere she doesn't know where you live... Maybe even make sure she can't track you down using social media.