One of the great things about the teenage years is your potential to do just about anything that you put your mind to do. The sky seems to be the limit, but the number of options is staggering. However, as you enter adulthood you realize that while you could do just about anything the reality is that you don't have enough time to do everything that might interest you. Eventually you have to make choices. This is not to say that one choice is better or worse than another. You are simply being pragmatic with your time. But each choice closes the door to other options you could have made.
For example, you might find a young woman you are very interested in marrying and decide to do so. Suddenly, a lot of things you could have done because you had no other responsibilities than yourself is now closed off. You won't be able to run of to Europe with a friend on a whim because you need to be with your wife and need to earn a salary to support the family.
A while back you made a choice that didn't include basketball. That is fine. But now that you see someone else who made a different choice that did include basketball succeed at it, you are wondering if you made the wrong choice.
Whether you try to go out for the team or not is up to you. You may or may not make it. There are a number of variables involved in the selection and skill is just one. But there is one thing you need to look within yourself and answer because no one else can do it: "Why are you going out for the team?" If the answer is because you love the sport and want to be involved, then great. But if it is just to show up this other person, then you will make a lousy team player.
What you are dealing with is envy. You want what someone else has for the sole reason that you think you deserve it more than he does. "A sound heart is life to the body, but envy is rottenness to the bones" (Proverbs 14:30). Envy causes discord, strife, and arguments. "For where envy and self-seeking exist, confusion and every evil thing are there" (James 3:16).
So drop all thoughts about this other person -- beyond the fact that he has shown it is possible to make the team. What you need to decide is where you want to go with your life. What is it that you really want to do? What is going to give you satisfaction of having done a job well? If basketball isn't high in your priorities, so be it. It doesn't make you better or worse than anyone else. There are limits on your time and energy and as an adult you can't do everything you dream of doing, but you can do well the things you decide to do.

