When I read this I laughed as it it me! Not really me, but I am just like that woman. And I hate it!!!!
I work in a school and talk with people all day every day, but they approach me (in person or on the phone). I have a very hard time approaching people myself. I do not know why, but I cringe everytime I have to make the initial contact with someone.
When I have to do this, I will work out in my mind a million times what I will say and anticipate their response. I work myself into a tizzy over the stupidest things. I guess it is a form of social anxiety. As another poster said, if I know the people I am fine, but if I am in a new setting with no one I know I am very very shy and standoffish.
I also hate cold calling someone - even people I know. Many times I will get my DH to call for me and then put me on the phone. If people call me, I am fine. Crazy I know, but I am now in my 40's and I feel I have improved somewhat. Not quite as bad as I used to be.
I am the Mom in the car on the cell phone. If the parent comes out to meet me I am fine, but I will not go to the door. DH is great at talking to people, so we make a great pair! He usually makes the initial contact and then will introduce me. We know how to make it work for us! It is not that I do not want to know the parents of my children's friends, I just cannot approach them myself.
Just remember we are all different and the OP's situation may be different from mine, but there may be a reason for it.