What do I do 3 weeks before vacation?

So, school is almost out, and my cousin invited me over to her house for two weeks this summer. I am not going to say where she lives, but there are lots of beaches there, and the average temperature (in Celsius) is anywhere between 24-38. I already made a packing list for the trip. I am going from July 3-16. That is 24 days away, so roughly 3 weeks. Since I am now almost at the 3 week point, I need to know what I need to do. I am a young teenager, so I don't need to make plans for pets, make plans for a house sitter, or the like. I am the only one going, so my parents and siblings will be home. Like I said, I already made a packing list, so what else do I need to do?