It may also be difficult for a birth parent to remember events, names, places etc. Giving a birth mother time to understand and put her own feelings into perspective will certainly make it much easier for her to discuss the birth father. Birth parents will usually be just as nervous as you are during a reunion. They too are worried about rejection, how they appear to you, and how you will both relate to each other. Some may be very open and discuss the entire history of their lives with you, others may need several months or years to feel comfortable.
Every reunion is different.
There are no rules. Getting to know a birth relative will take time. There are several resources and support groups in most major cities that may be very beneficial in receiving support and understanding from all members of the adoption circle. Reading material on adoption and reunion is very extensive and most public libraries have a good selection of various adoption-related literature. Support groups and reading about adoption and related issues are very helpful, both prior to and after a reunion.