Chemistry: The Central Science (13th Edition)

The average distance from the nucleus of an electron in orbital $2s$ is smaller than that in orbital $3s$.
The radial extension of electrons increases for higher shells (greater value of $n$). That means the average distance from the nucleus of an electron in an orbital of lower shells is smaller than that in an orbital of higher shells. Orbital $2s$ are of the second shell ($n=2$). Orbital $3s$ are of the third shell ($n=3$). Therefore, the average distance from the nucleus of an electron in orbital $2s$ is smaller than that in orbital $3s$.