Improving UX with views exposed filters: automatically selecting certain options based on a profile value
As a huge fan of direct approach and writing own helper modules, I would make it happen mostly with jQuery.


Outputting user's age or age category in a hidden &lt;div&gt; is easy. You can append it to view's form with hook_form_alter, or simply output it as a block that will never really be seen.
Attach your JS library to views form (or again - simply load it and make it see if form is on page)
In behavior, read user's age from &lt;div&gt; created in 1. and based on that check checkboxes. Invoke click() on them for full emulation of user interaction (i.e. to reload what would get reloaded if it was user who selected it).