Answer:
When I was younger.
Explanation:
The dependent clause is also known as subordinate clause. The subordinate clause is the clause or a group of words that contains a subject and a verb. These sentences of clause do not make a complete sense or convey a meaning.
In other words, a group of words that cannot make sense or can not stand of there own are known as a dependent clause or a subordinate clause.
In the given sentence, the dependent clause is "When I was younger."
These words do not make sense of their own or do not convey a complete meaning.