It is common for students to overshoot the endpoint, meaning they add too much NaOH(aq) from the buret, which causes the solution to turn bright pink. What specific impact does this mistake have on the percent of acetic acid result?

the percentage of acetic acid will be low.

Explanation: The major aim during titration of acids and bases is to  determine the endpoint , that is exact point where the acid  in the beaker changes colour, (in this case, pink )with an additional  drop from the burette containing the base, since it is usually difficult to mark the equivalence point that tells us when  all the substrate in the beaker has been neutralized completely with the buretted substance.

Overshooting the end point is  an error which can occur when the person involved in the  the titration accidently goes beyond this  endpoint by adding too much of the substance(base) from the burette into the beaker missing the exact endpoint.

This implies that the person  has  added too much of the burreted liquid, ie the base than required  , making the acid in the beaker to continue to react resulting  to a lower concentration of the acid (acetic acid)  with excess base.(NaOH)