System Restore is two operations:
The first is a "System Snapshot", which is a record of the system state (or parts thereof) at a particular moment in time. This can be system initiated or user initiated (manual). In both cases, it is obviously impossible to select anything other than here-and-now for the snapshot (System Restore Point).
Having created - over time - a body of System Restore Points, the second operation - System Restore - can be invoked manually.
This involves selecting, from the available historical "snapshots", a Restore Point that meets one's needs.
It is clear that you cannot select a Restore Point unless it has been created manually or automatically in the past.
You cannot roll back to a state prior to your earliest Restore Point (at least not without the help of Mr. H.G. Wells!).
SD