How to access array element in pgsql after array_agg

Hello,

I wanna ask how I can access array element in array_agg ?

I do select array_agg(ids) from x;
in ids I have int and result is :

array_agg
-------------
{3843,2,3543,33}

I want to access one element or first one direct in sql query like:

select array_agg(ids)[1] from x;

and to receive int value 2

Any hints how I can do it ?

And also for performance did that is good I to do it in SQL or I should
do it in language that I use ? The result in query will return about 2,
3 million rows.

Thank you,

Cheers,
Hristo S.