Upvote:3
48 Star Flags were flown from July 4th 1912 when New Mexico(1911) and Arizona were added to the Union until July 4th 1960 when Alaska(1959) and Hawaii became states. By law the flag changes on the subsequent 4th of July following a state's addition to the Union.
So given the dates that means your flag could have flown during The American invasion of Mexico in 1914, WWI, WWII or Korea. Or of course on somebody's front porch during that time period.