Answer:
The age of brother is 3 years .
Explanation:
It is given that:
The age of your brother is: y years.
The age of older cousin's are:
and
year old.
Also, the difference in the ages of the cousin's is zero.
This means that:

Now, as y is not equal to zero.
( since, the age of brother is older than 1 year old)
Hence, y-3=0
⇒ y=3.
Hence, the age of the brother is 3 years old.