I'm not entirely sure which 'her story' you are referring to. Different stories can have different lengths depending on various factors like the complexity of the plot, the amount of dialogue, and the reading or playing speed. If it's a game story, you can usually check on gaming platforms for an estimated playtime.
There are so many variables when it comes to determining how long it takes to 'beat' a story. If 'her story' is a simple linear narrative, it could be over in a matter of minutes if you just skim through it. However, if it has a deep and intricate plot, numerous characters to keep track of, and perhaps some interactive elements, it could take a significant amount of time. Let's say it's a story -driven game. If the average player takes about 10 - 15 hours to complete a similar -sized game story, then it might be in that ballpark, but again, without more information, it's just speculation.