I purchased a refurbished MacBook Pro for my daughter. I am looking for a case to fit it but I have no idea which generation it is. I have tried to find that online, but I haven't found it. I don't have the serial number, only the model number? I do I know which one it is so I can search for a case? Also any recommendations for a case that is actually something that the computer stays in as it is being used. She has a 3yr old son....I'm thinking it needs protected.