If you are broke, you need to wait until you get enough money to buy paint. If you're only 13, you need to be a little more patient with the things in your life. But you can reduce the amount of furniture you have without spending any money, so that's what I'd do first, if I were you. I'm still creating my dream room(s) - and I'm 72 years old. Enjoy your life and don't pin everything on dreams.
Think about how you could rearrange the furniture to give you more space. Get out a piece of paper and draw up potential designs. Then ask for help moving things around so that you don't hurt yourself or scratch up the floor.
How do I make my room perfect I need new paint and less furniture and carpet but I'm broke and only 13