Anyone can get better at something if they practice and try hard at it. You cannot expect yourself to get better at any sport for example if you do not play a few times a week and know how to play the game properly. If you become a member of your school team, it is a great way to practice and make friends at the same time. It is a great opportunity to get better at something that you are interested in and get help from people who know what they are talking about.
If you do not have one already, you could try encouraging your family to buy a hoop for your yard. That way you can practice with your dad or one of your siblings. If no one wants to play with you or no one is available to, you can always practice your shots on your own time. Try taking breaks from homework whenever you can and go outside for a few minutes. It will help you get some exercise and you will not go crazy when you have to sit down and crank out homework for a while without breaks.
If your parents encouraged you to play and you do not want to then you can always make a compromise with them. If you sound mature about it then they will most likely be impressed with your maturity and compromise with you as well. When parents push their children to do things, all they want is for their children to explore different options and be healthy. When they make you try out for a sports team, they want you to be active but they also want you to explore things that you might be interested in.
It is hard to know if you like something until you try it. You may think you will like something and hate it or think you will hate something and love it. If you try it and still do not like it, then they should have no problem with you not progressing any further with it.