Is it normal for a teen boy to want to see his sister naked?

This happened when I was 15. And before you pass me off, hear me out. This is serious and I am being completely honest. Over the last year or two I have started to wonder what my now 14 year old sister looks like naked. Last summer, I went too far and put a camera in her room when she was changing, and she found it and called me out on it. I felt terrible, and she agreed not to tell our parents. Then, This christmas time we were sharing a room at my grandmother's house. There was a bunk bed, i had the bottom, and I had a blanket hanging so that it enclosed the bottom bunk, except for the end of it. My sister got out of the shower, knowing I was in the bed, because I was singing and makin it blatantly obvious, and she started to get changed in our room. The open end of the bed was facing a mirror that was at just the right angle that I could watch her change, but she couldnt see me. I saw her hairy pussy, which was nothing special, but then she turned around, and she had the most beautiful breasts I had ever seen. Ever. And i was sexually attracted to her naked, Not in a way where I wanted to do anything with her, but she was so pretty naked, and I was so blown away because I ha never and still don't see my sister as having an attractive face. Is it normal to enjoy the sight of my own sister naked?