This past weekend I was visiting my sister at her college campus. We had planned that weekend for months as the soccer team I support was playing only 10 miles from where she lives. Anyway, I went down on the friday night and stayed til Sunday morning before heading off home. Went out on Fri night with her and her flat-block mate, Kathryn. Kathryn is around my age (I'm 21, shes 20, and my sister is 18) and although we didnt fool around on Friday night we got on well. Saturday night, I noticed her checking me out alot and one of my sisters other friends had mentioned this to me later on in the night - noticing that we seemed to have a bit of sexual chemistry between us two. Anyway, when my sister went to the toilet I told Kathryn that I noticed she had been checking me out and told her I thought she was a great girl and that I'd like to take her out sometime. We kissed then. Only problem is, she told me to keep it quiet from my sister, but my sister already knew as her other friend (the one who told me about the sexual chemistry) had took her to one side and said 'I think Ben and Kathryn like each other' - and she told me she was cool with me taking it further if I wanted to. I left early on Sunday so didnt get a chance to speak to Kathryn, I got a text on my way home from her asking if I had told my sister about us two, and when I said she knew already, she asked why I'd said that. I told her it was because me and my sister are close and are cool with stuff like that (which we are) and then I asked her if she would like to go on a proper 'get to know each other' coffee sometime. She then replied saying that if I wasnt her friends brother she would have no hesitation in doing it and that she liked me too, but she said it would be awkward if we did get together due to that fact. I'm stuck in two minds about what to do. As far as I know Kathryn and my sister havent spoken about what happened on Saturday night yet, so she might be a bit paranoid about what my sister will say. On one hand I'd like to chase up our initial feelings for each other - and its frustrating as I know she feels the same way about me, and on the other hand I dont know if I should respect her worries that it might be awkward if we do get into a relationship. I've not spoken to her since she texted me that, other than to say 'if you change your mind, let me know'. I'm thinking of calling around Wednesday to have one final shot at it. What do you guys think I should do? Its all a drama over nothing. Kathryn is worried that it'll affect her and my sisters friendship, or me and my sisters bond, when me and my sister are actually cool about the whole deal.