I'm going back to the start

I've been looking at you closely lately, trying to remember the details that make up who you are. The way your hair sticks up in certain places and the small curve of your bottom lip. The way your eyes close a little bit every time you smile at me. It's things like these that make me wonder what we're doing here. Why is it that the earth has been around for billions of years, but we're only here now? I've been remembering the details that make up who you are just in case you're not around one day.