Paul,

I find it useful to use this search pattern -- search for a child's given name, together with both parents' given names, omitting the surname -- to find families where the surname may be recorded or transcribed incorrectly.

Also note that "Poland" during its history ceased to exist, so adding Poland as a country may be counter-productive.  The FamilySearch engine in particular will eliminate possible matches if you include data that doesn't match.  When using FamilySearch, it is best to enter the minimal amount of data, then filter to reduce the number of hits.

In this case, searching FamilySearch in NY for a person named Shirley (leaving surname blank) with parents Ben & Sarah turns up this 1930 census entry for Shirley Shapin:  https://www.familysearch.org/ark:/61903/1:1:X7DZ-L4V .  It appears to be the family you are interested in, though the older son's name is different.  FamilySearch then suggests this entry for the family for the 1940 census:  https://www.familysearch.org/ark:/61903/1:1:KQ5N-N4P .  The surname was recorded as "Shapiro" by the enumerator, but, again appears to be the same family, with the addition of a younger child named George.

Regards,
David Oseas

Researching:
HYMAN/HEYMAN/HEIMOWITS/CHAJMOVITS: Zemplen-Dobra, Hungary > New York
KLEIN: Satoraljaujhely (Ujhely), Hungary > New York > Los Angeles
KRONOWITH: Hungary > New York
OSEAS/OSIAS/OSIASI/OZIAS: Iasi, Romania > Chicago > Milwaukee > Los Angeles
SCHECHTER/SHEKTER: Kishinev, Bessarabia > New York  
SHERMAN: Iasi, Romania > New York > Los Angeles
STRUL:  Iasi, Romania > Haifa, Israel
WICHMAN: Syczkowo (Bobruisk), Belarus > Milwaukee > Los Angeles