Is cataract simply aging?

There are quite a few elderly people around who have had cataract surgery.

Is cataract a disease caused solely by aging?

Is this a condition that can occur in teenagers and people in their twenties?

My mother also has cataracts, but she has not been advised to undergo surgery yet.

I'm wondering whether it's better to endure some discomfort and delay surgery as long as possible or to have it done as soon as possible so I can see a clear and bright world.