Gonna buy hunkal, but have a few doubts

1)So im soon gonna try out hunkal aranya for the first time the problem is that I do not have a good grinder at home so I have to get the coffee grinded from a local coffee shop in batches of 250 grams or 300 grams I am just afraid that if I get the coffee pre ground at I will affect the taste of the espresso which comes out compared to when the coffee is ground freshly just before making the espresso. So if any one of you can help please let me know if it will affect the taste substantially. 2)will keeping the coffee beans in the fridge increase the shelf life 3) does buying 1 kilo beans make sense