Is it normal to have sexual fantasies with those close to you?

Whenever I need to cum, I generally tend to make up stories in my mind, such as orgies/sex parties/secret sex. However, the people who are in my fantasies are always those whom I'm close with.... Such as my neighbor's mom, my aunt, my childhood friend/her mom, and my really good family friend. I don't know why, but I think that the fact I know them so well makes me want to have sex with them... Is it normal that I associate sexual feelings with those who are close to me? It gets me off fastest..