I know what you mean, Jen. I couldn't talk to either of my parents growing up so I kept everything bottled up for awhile until I was able to find some supportive people to help me and to share stuff with. My parents just didn't handle any personal problems or "negative" feelings that I had very well. Although I knew they loved me, they couldn't show me. It's always been hard for them to do that.
I think if you continue to be there for her, marlsy, she'll open up some more. She's very lucky to have a loving, concerned Mom like you.