Yes, age matters. Article 4 of the convention states that the convention ceases to apply as soon as the child reaches the age of 16. That means that a trial started when the child was almost 16 years old is of no use when the child reaches the age of 16 before there is a court decision.
The age of the child can matter in other ways as well.
For example, in an international child abduction case, the Dutch court will invite the child to a child interview when the child is six years or older. If the child is under 6, the parents can request the court to hear the child.
Art. 13 part 1 b of the convention
Article 13 (1) (b) of the Convention states that the return of a kidnapped child can be refused by the court if there is a serious risk that the child will be exposed to a physical or mental danger when he returns to the country of his habitual residence, or is brought into an unbearable condition in any other way.
The young age of a child may be important in this regard. The young age of a child may be important in this regard, but it is not decisive in itself. In addition to the young age, there will have to be additional circumstances. This is also the case when a very young child will be separated from the kidnapping parent after returning to the country of origin because they will not return. The young age in itself is not enough to conclude that the child will be in an unbearable condition upon return.