My front tire is 24×2.10 and my back is 24×1.95 should I leave them like that, or should the larger be in the back ?
This is relatively common amongst mountain bikers. A narrower faster rolling tyre in the rear and a wider grippier tyre in the front.
On road bikes you often see the opposite, a wider tyre for comfort in the rear and a narrow tyre for aerodynamics in the front.
As long as the tyres fit your bike and don't rub it's entirely up to you to run whatever combination suits your riding best.