Whatever your stack is in relation to the blinds changes the game you are playing. It will have a huge effect on which cards you should be playing and how you should play them.

Playing the shorter stacks is generally simpler than playing the deeper stacks.

It is generally agreed that deep stacks afford you more risk and more learning opportunities.

Whatever stack size you decide to play you should probably be consistent with - as one lesson you learn at one stack size may not translate directly to playing a different stack size.

Most of the posters and the advice you get on this forum will expect you to be playing a 'full' stack of 100bb. The advice you get will be mostly applicable to 100bb play and if you play mainly 20bb you will occasionally receive advice that will be outright wrong.