Due to the fact that existence is real, you can prove that the existence has been around for infinity. First though, we have to define a couple words:
1. Nothing - Nothing is a word used to describe the absence of existence. It is not a tangible object and it is impossible for the human mind to fully realize the concept of nothingness. If you hold out your hand and it is empty, you would say that there is nothing in your hand. This is only partially true. There is nothing in the sense that there is no physically object in your hand, but there is still something there, space. Now imagine for a second that you really could hold a ball of nothingness in your hand. Firstly it wouldn't really be a ball, because then it would be something instead of Nothing. You couldn't see it, feel it, taste it, or sense it in any way. If you can do any of those things, then it's not Nothing that you are looking at. To imagine where Nothing is, you have to step outside of everything. It would mean traveling to the tenth dimension and then going up one more dimension, which is impossible due to there being nothing there to go to. The only reason Nothing exists, is because we can clearly experience Something.
2. Something - We and everything in all possible universes and all possible time lines make up Something. We know and can prove that it is real just by existing. Something is the only thing we have ever known.
3. Lomonosov Lavoisier Law(LLL) - LLL is the law that states that matter cannot be created nor destroyed. All the matter that exists in any given system will remain constant regardless of the forces acted upon it.
Those three words are the only thing we need to prove that Something has always existed.
To start with, we can see that at this current point in time that matter clearly exists. It makes up everything in the universe.
Please note that conventional time that we recognize came into existence with our universe. For the rest of this article, you have to imagine all of existence (all possible time lines in all possible universes) as one massive time line.
Now imagine this massive time line with you standing in the middle of it, the middle representing the present time that you are existing in. At this moment, matter exists or you wouldn't be imagining this time line.
Now start moving forward on the time line. LLL says that matter cannot be destroyed. With this in mind, when will you get to a point in which matter no longer exists? Even if you were to make it past the death of the universe, matter would still exist in some form or the other because it is impossible for something to become nothing. With that we just proved that Something will always exist, although it doesn't necessarily have to form anything that we are familiar with.
Back to the center of the time line. This time, start moving backwards in time. Since matter exists in the present, when will you get to a point in which matter formed out of nothingness? You won't. You can go back to before the big bang if you want, it doesn't matter how far you go back because it is simply and completely impossible for Nothing to form Something. You cannot get Nothing from Something, so therefore no matter where in time you go, you will never find absolutely nothing.
Since there was never a beginning nor an end, there is no need for a "creator" of any sort. Matter(existence) has simply always existed in one form or the other, or it would never had existed at all. Matter will last forever because Something can never become Nothing. Get it?