The argument you presented is known as the cosmological argument and is often used to support the existence of a god or a creator. However, it is important to note that atheism, by definition, is the absence of belief in gods or deities. Atheists do not necessarily accept the cosmological argument or any other arguments for the existence of a god.
Regarding the concept of time and the beginning of the universe, it is true that our current scientific understanding points to the Big Bang as the starting point of the universe as we know it. The concept of time as we perceive it is closely related to the nature of our universe and is a subject of ongoing scientific investigation.
However, it is crucial to distinguish between the concept of time within the universe and the existence of a god or a divine being. The existence of time does not necessarily imply the existence of a god. There are alternative scientific theories and philosophical viewpoints that explore the nature of time and the origin of the universe without invoking a supernatural deity.
Atheism is a philosophical position that focuses on the absence of belief in gods based on the available evidence and arguments. Atheists may approach questions about the origins of the universe and the nature of time through scientific inquiry, critical thinking, and empirical evidence, rather than invoking a god as an explanation.
It's important to remember that discussions about the existence of a god or the nature of the universe are complex and multifaceted. Different individuals may hold different beliefs and perspectives, and it is essential to engage in respectful dialogue to explore these topics further.