[great oaks from little acorns grow] As great oak trees grow from tiny acorns, so many great people or things grew from a small and unimportant beginning, so be patient. […] A Dictionary of American Idioms

grow

[grow] See: [GREAT OAKS PROM LITTLE ACORNS GROW], [LET GRASS GROW UNDER ONE'S FEET]. A Dictionary of American Idioms

little frog in a big pond

[little frog in a big pond] or [small frog in a big pond] {n. phr.} An unimportant person in a large group or organization. * /In a large company, even […] A Dictionary of American Idioms

from little acorns

[from little acorns] See: [GREAT OAKS FROM LITTLE ACORNS GROW]. A Dictionary of American Idioms