Does she have to execute her father's will that she should marry her cousin (son of her paternal aunt)

My father (may Allaah have mercy on him) left a will saying that I should get married to my paternal cousin, but my father did not ask me before he died about my opinion concerning this person, because he got sick and then he died, which prevented him finding out my opinion. As for the person concerned, I told him frankly when he brought up the subject with me that I had nothing for him but feelings of brotherhood and kinship. Am I going against sharee’ah? Is it disobedience to my father if I do not marry this man? Please note that my heart is inclined towards another relative who respects me and is kind to me.