My sister really badly needs coffee in her life but does not like the taste, how can I get her start drinking it?

My sister is a heavy sleeper and is hard to wake up when she has to go to school. Even during school she falls asleep in the middle of class and her grades are suffering because of it. The teacher suggested she should drink some coffee before class so she can stay awake and pay attention. The only problem is she does not like the taste of coffee and refuses to drink it. My sister is kind of a sweet tooth. Her preferred diet consists mostly of sugar and starches. I thought of using Mountain Dew to wake her up but I don't want to encourage her unhealthy dietary habits. Do you know of any way to get a coffee hater to start liking coffee? Is there any brands that will turn a hater into a lover? What made you start liking coffee?