I started 9th grade in 1969. By the way, old does not equate to valuable. Value is a function of supply and demand. Some "old" coins were saved in huge quantities in mint condition and are not as valuable as similar "old" coins with lower mintages. (An example is the 1883 Liberty Nickel Without Cents.)
The long awaited 6,961 "Upside Down Washington" error! Nearly 5,000 years away from being minted... it could be worth anything you want for it...
Are you referring to the 1776-1976 bicentennial quarter? If so, and it is a circulated quarter it is worth face value. One in Uncirculated condition or a proof coin would have some value.