My sister has a dog she wants to give me.

I have pets. When I go off on a little trip I make arrangements for my 4 legged friends. As a rule my step-granddaughter comes by after work and fills the bowls and cleans the cat litter.
Now my sister is moving, and insisting I take her Apple Head Chihuahua.
I was hesitant. She is only able to bring one pet to the condo. I don't know this breed. Does anyone in here know much about them? She sounds cute. Yet something is holding me back. Sister is moving into a Condo and is limited on the pets brought in. SO, even if I were to find another home for little Nellie, My sister would be horribly upset with me. Scared to death I might step on the little tike.
I did hint to her that making this commitment sight unseen as not something I do lightly... and she then gets angry with me.
Any thoughts from the Audience?