Am I in the wrong for not coming out to a friend?

Hi, I'm new to this forum and I'd just like some people's input on this frustrating situation.

This happened awhile ago back when I came out to a few of my old friends, and to this day it still bothers me. So, I came out as bisexual to two of my friends from high school and they were genuinely surprised because they didn't suspect me of being attracted to other women. (I've figured out that I'm leaning towards the women attraction side of the spectrum, I think I consider myself as lesbian but I'm still a bit confused) anyway, the next day.. one of the friends that I came out to, decided to out me to her best friend when I specifically told her not to but I let it slide since her excuse is that she tell her best friend everything (I was a bit upset at this). So continuing with the story, the friend who outed me told me that her best friend felt left out that I didn't come out to her and they proceeded to guilt-trip me and kept telling me that I made her sad and that I need to come out to her, and I felt very frustrated because it's not an easy thing to do, and I didn't see the point in coming out to her, when she already knew the truth.. so I didn't tell her personally. I don't know, was I in the wrong? Should I have come out to her even though she already knew my sexuality?