The past does not really exist. This means that the future does not really exist. This is because you cannot have a future without a past, just like you cannot have an inside without an outside.
But YOU exist. YOU KNOW this to be TRUE and furthermore this is the only fact that YOU really know. So if YOU exist, then you must exist NOW and not in the future or the past.
To exist in the dimension of NOW, without a future or past, means that you are Eternal. On the other hand, what does exist in the past and the future are your acquired personalities, which are processes running in your mind and are not eternal.
And, if you believe you are these personalities, then you may unknowingly believe that you may not continue.