How do you think the communication should be between a mother and her 17 year old daughter?

I think my mother is an incredibly nosy woman and I really wish she would just back off sometimes. However, if I am just being an overreacting teenager I want to know so I can work on myself then. But basically whenever I get together with a friend she always asks what we talked about she she wants a thorough description. My mother is a minister who also does counseling so whenever she does this I ask "If I tell you then you have to tell me exactly what you talk about to everyone who sees you for counseling." However, she doesn't see the point I am trying to make because apparently what her "patients" say is more important than what my friends say to me. Which I am sure it is obviously if they need counseling for it but still that doesn't mean I have to tell her! Also, my mother has no reason not to trust me. I don't drink, smoke, do drugs, have sex, or have friends who are bad. So I don't know what to do about this. After I get on the computer she will probably also check the history so basically if I want any privacy I have to delete it. I don't look at porn or anything I would just delete stuff like this. Anyway, if maybe I could have some opinions about the situation. Maybe some advice on how to handle it or how to change myself. Thanks!