You can shower too much.
Showering too much can actually remove the natural skin oils from your skin and dry out your skin.
However showering once per day or twice per day is usually not a bad thing.
But it's also good to sometimes skip a day of showering if you're not really dirty.
But there's no harm in showering everyday or twice per day if you need to shower that often.
Just make sure to use a moisturizing lotion or moisturizing soap when showering to keep your skin from drying out.
Showering or bathing too much removes healthy oil and bacteria from your skin, so bathing or showering too often could cause dry, itchy skin and allow bad bacteria to enter through cracked skin.