To find the median age, we need to arrange the ages in ascending order and then determine the middle value.

Given the frequency distribution:

\(\begin{array}{c|c}

\text{Age} & 20 & 25 & 30 & 35 & 40 & 45 \\

\hline

\text{Number of people} & 3 & 5 & 1 & 1 & 2 & 3 \\

\end{array}\)

Arranging the ages in ascending order along with their frequencies:

\(20, 20, 20, 25, 25, 25, 25, 25, 30, 35, 40, 40, 45, 45, 45\(

There are a total of \(3 + 5 + 1 + 1 + 2 + 3 = 15\) people in the distribution.

Since there are an odd number of data points (15), the median is the middle value. The middle value is the 8th value in the ordered list, which is 25. Therefore, the median age is 25.