Piss off

It should be a happy thing to prepare a wedding but it's not as easy..why? i was talking to my sister about my wedding and i wanna know when she can come to my wedding and she said not sure...ok, fine! then she asked if i talked to mom about it and i said not yet....but then she said...your fiance should talk to mom about it..and i said we don't know...and she said...how would u not know??? even if u guys don't know, his mom should know..and i was like... what the heck! don't give me grieve! i am not a traditional person and why would we know about that? and we didn't talk to his mom about it...i thought wedding is just me and him, well, of course we have to involve the family too but don't give me an attitude!! and her response was....this is called politeness and then mention about the $$... OMG..i had enough from her alrdy..if she doesn't want to help, then don't even bother.  I'll set a date and if they can't come, too bad!