Welcome to Atheist Republic youngatheist_89.
First off, I must caution you to protect your true identity and where you live. There are some who take offense at apostates.
One does not have to give testimony (although it is welcome and appreciated) on being an atheist, we just are what we are, ones who lack a belief in a god or gods.
For myself, I visit this place for many reasons. The most important for me is that I learn. I learn about the many errors and lies in holy books, how they do not make sense, and the harm religion causes.
I am sure you are aware of the harm to many who do not adhere to a religion, they can be persecuted, ostracized, even murdered. There are multiple levels of harm, apart from the obvious ones I stated. Hang around, you will learn a lot about such.
The only requirement to be an atheist is lack of belief in a god, that is it. Some may be polite, some not. Some may wear jeans and a t-shirt, other suits and ties.
You mentioned you feel free after leaving the cult of Islam. I was a devout theist, and once I realized I was an atheist a great weight was lifted off my shoulders. That is because the Abrahamic religions (Jews, christians, Muslims) are taught that one will be punished for eternity if they do not bend the knee.
I now believe there is no after life once I die all I ever was is gone.
And from that simple fact I feel even better, because I savor every moment, cherish personal relationships, and enjoy the simple things in life.