Q:

Taking Source Charge As a Reference Point In Deriving Electric Potential?

Just like while calculating gravitational potential energy, we take earth's potential as zero and with respect to that we calculate potential at a point. Similarily in electrostatics why can't we take source charge's potential as zero and not infinity.
Also will the potential at a point a point $R$ near charge be different if we take zero Potential at source charge or at infinity?

A:

You can place the zero of electrostatic potential almost anywhere you want.  You can't place the zero at the location of a point charge because the potential is not defined there.  But a point charge is an idealization.  For all practical situations you can place the zero anywhere.  But it's much more convenient to place it at infinity.  That way the zero is the the same "place" (if infinity is a place) for all objects in question.

