How can I find out if there was a will made after the death of my mother?

My mother died within the past 30 days or so. She had two children, I'm the oldest. We hadn't talked to each other in nearly 20 years due to we were never close. I was told from time to time throughout the years on things going on in her and my sister's life through my mother's sister. Her passing was purposely kept from me because we were never close. How I found out was my mother's sister to who I am close to and who has the beginning stages of dementia, slipped and told me during a visit I had with her. My Mother and sister and I all live in the Dallas area in Texas. I would like to know if there was a will made how can I get a copy? If there wasn't a will made, what are my options? I know she owns a house and after her third husband died a little more than years ago that my sister was placed on the deed, supposedly I have no proof of that, just was told of that when I found out of her passing.