Is it normal that i'm worried about my relationship with my sister?

When I was 6 my dad left my mother and myself to pursue a new relationship. He had children, though as far as I was aware, they didn't know about me.

A few months ago however, I had a phonecall from a woman named "Sarah" who said that she was my half sister, and wondered how I'd feel about getting to know her. At first I thought I was uncomfortable about the idea, but I soon came around and thought it's not her fault that the situation turned out as it did, and it could be very enlightening having a sibling in my life.

I gave her a call and we decided to meet for coffee. At first it was very awkward, but soon became completely natural, and we were talking like we'd known each other for years.

After a series of meet-ups, she invited over to her home. I spent ages making sure I was presentable, and was dreading and surprise visit from my father. Luckily, this didn't happen, and she planned to make a fantastic lunch. When looking through the fridge she discovered that she was out of eggs, so nipped down the local shops to re-stock. I felt really honoured that she trusted me alone in her home, as essentially I was a stranger.

During this time however, I feel I may have broken this trust, by eating her Yorkshire Terrier.

At the realisation of what I had done, I couldn't carry on the day, so left an appologetic note by the phone, and made up an excuse to leave before she got back.

I'm not terrified at the thought of explaining what happened that day, and am worried it might have an effect on our relationship.

Is this a normal fear?