Co-Owner of a house do i need to put it on my taxes?

My mother was the sole owner of the house a couple of months ago, but she wanted to refinance to lower her payments. So i decided to be a co-signer since she didn't make enough. I do make more than her. So now i'm co-owner of the house. What advantages or disadvantages is there for being a co-owner? When i fill out my taxes do i put down that I bought a house recently or that I'm owner of a house? Do we both get to deduct expenses for the house or we split it up in half or only one of does it in our tax return? Any other information will be appreciated, if any have a book or website that will answers most of my questions i will appreciated too.