When should I start taking mock exams?

Hi all,

How far in advance would you suggest beginning mock exams (for a first attempt at CFA Level 1)?

My current plan means I would finish going through each topic twice (incl. Q practice in the second round), with 3 weeks to go, so I plan on doing mock exams then. Is that leaving it too late? I don’t see the point in doing a mock before I’ve done Q practice on all of the material, but don’t want to stress myself out by leaving it too late either.

Grateful for any advice - thanks!