Please help my crisis! I'm having trouble deciding on a carpet/paint color for my room. (teen)?

You also have to consider the resale value of your choice so that you don't have some wild color in your room that will affect selling your home later. White carpet is a disaster, I've had it in my own home and done in for clients. About 6-8 months after installation you will notice what is called "hat banding" which is a line of dirt that aculates all around the perimeter of the room. This is dust that settles there that most vacuums can't reach. Tan, beige, sand, and taupe are the most popular colors of carpet because they do not affect resale value, but are difficult to keep clean because stains show. If you like the beach theme idea, you could go blue carpet and beige walls. Dark blue won't show stains.