What would be a good batting average for a varsity freshman that wants to play D1 baseball

That is not an easy question to answer as it all depends. It depends on whether or not the player continues to improve, the normal D1 doesn't care what your average was as a FR but as a JR & SR. It also depends on where you play and what competition you play against. It also depends on how you field and how fast you are as top flight fielders and speed burners will normally get a slight nod over a not as gifted player with the same batting average. It can depend on attitude and how you get along with the coaching staff and fellow players. It can depend on work ethic and hustle. And it can depend on grades as most D1 coaches don't want a player they have to baby sit to keep in school.