yeah..I think this is okay!

oh I understand how you feel about having someone else coming with no experiences around kids/cats etc so you're not weird!

maybe you could talk with your sister in law and explain her how you are feeling about that and to have them come over and see how they do with your animals first before you go off. hopefully that would be a good outcome so you'd be less nervous...!

but if things didn't look good...erm.. then there would be something you'll have to do about!

whatcha think?