I'm planning to throw my non-vegan sister a vegan baby shower
Who are you inviting to this vegan baby shower?
I will invite my vegan friends and some of her other friends.
It's understandable to want to throw an event for someone, but you shouldn't force your ideals on them. If the event is for them then you should be considerate of the things they like. They may feel like you're trying to force them to do what you want them to do.
I want them to go vegan so it's not that big of a deal.
You have to take into consideration that not everyone wants to be vegan, including her friends. Would you like it if someone forced you to eat meat?