All beginner guitarists struggle with switching between chords at first, thats part of the learning curve. Here are some tips on the subject, but make sure you watch our video lesson on how to change between guitar chords, where I will show you the correct technique of learning chord changes. Watch my hands closely to see the correct method.
The main reason beginner guitarists experience difficulties when switching between chords quickly doesn't really have that much to do with their fingers. The main problem is that beginners haven't learned to visualize which chord they're about to play, and which fingers they'll need to move. This means that once they get to where they would need to change chords, they start thinking about which finger goes where, which means that there will be a lag between the chord changes.