[DELETED]

First of all, welcome to YWS! I only joined a few days ago, but let me know if you have questions or need reviews or a friend.

This was short, but it was good!

Here are some nitpicks first:

physically silenced forever more

What do you mean by “physically?” I feel like it’s a bit unnecessary. Maybe you’re referring to the afterlife, but you did say “your body,” so that implies physicality already.

Could I do it? I was yet to believe there was a real reason to, but it didn't prevent me from feeling like it was something that needed to be done. Simply, I have no purpose for being on this earth.

I’m not quite sure what you’re trying to say here, and the “yet” makes it awkward. There’s a difference between being able to do it, and having a reason to do it.

My life has been too perfect for me to make anything worthwhile and productive from it, from the world I've been forced to grow up with in, from the continuous routine I've been expected to live up to.

Besides, I was am much too young for my death to make a serious impact on anybody else's life other than my own.

What about his/her family?

My mind is cleared, heartbeat softened, fear wiped away, tears non-existent, breathing even.

Because nNone of it matters;

One step that I've already took taken.

Goodbye.

I think it would be stronger if you took this out, ended with the sentence before.

General
This is a really good start. You're a good writer, especially if you're only twelve! I think you could expand it and make it even better, though.

Have you heard the writing advice, "show don't tell"? It's pretty common advice, but it's easier said than done. Basically, I feel like you're doing a lot of "telling" here. You tell us the character is despairing, you tell us s/he feels his/her life is worthless, you tell us s/he commits suicide. You should try to show these things. Either start farther back and show us his/her life, or start where you do and give us flashbacks to his/her life. And look at this:

Mind cleared, heartbeat softened, fear wiped away, tears non-existant, breathing even. As for myself? I'm ready. I am ready to die, face death, commit suicide.

In your first sentence, you show us s/he is calm and ready to die. And then you go on to tell us the same thing! It shows more respect to your readers and makes your work more interesting if you show more and tell less, so we can figure it out on our own. We can read that first sentence and say, "This person sounds relaxed. They must not be afraid of dying." That make sense?

Another thing you want to consider: what really happens here? Yeah, I know, somebody kills themselves. But the basis of fiction is that the main character, the protagonist, goes through some sort of change. This process is drawn out and complicated in a novel, with lots of plot twists, but a short story gives you the opportunity to get close and magnify this change. The problem with your story is your character starts out wanting to die, still wants to die in the middle, still wants to die at the end, and then dies. S/he never once has any doubts. A simple solution would be to have him/her want to die, then not want to die, then want to die. And don't just tell us s/he does or doesn't want to die, show us, and show us why, too. Show us the bad things about his/her life and show his/her calmness - s/he wants to die. Show us the good things about his/her life and show him/her getting nervous, feeling sick, backing away from the bridge or whatever - s/he doesn't want to die.

I hope this was helpful! Let me know if you have any questions, on this or YWS stuff.
Prolix