Is it normal to like your best friend's sister?
Basically, I just turned 18, am in my first year of college, and I have a crush on my friend's little sister. She's a senior in high school, but we're only six months apart age wise, so that's not the problem. The problem is that she's my best friend's (my grade but older than me by almost a year) younger sister, and I feel really terrible about it. I know her pretty well so normally it wouldn't be that weird, but I feel like I'm betraying my friend by liking her. I don't know how I can look him in the eye keeping it from him. I've tried to suppress and ignore these feelings for a while, but to no avail. Is this normal or am I a screwed up person? Also, should I tell him, or hold it in?
Some additional info. Before anyone gets ahead of themselves, I'm not looking to just sleep with her, my feelings are emotional. I've never had a date, and I'm a virgin, so I have little experience with these things and these circumstances only make it more complicated.