In 27:2-4 Yitzchak tells Esav, "I am old and do not know the day I will die... Bring me food I enjoy so i can bless you before I die."
Yitzchak was not going to die today. As Rashi says, he was 123 years old and was unsure whether he would live until 127 like his mother or 175 like his father. Either way he still had plenty of time left (and he ended up living until 180).
So why did he request the food and deal with the brachos right now as if he was about to die?