i normally castle when i need that rook

My opinion is:castle early only if you know your opponent is weak.And move the pawn one square

i sometimes would but i would move my pawn to g3 instead of g4

Personally, I don't.  I usually wait until I can see the general direction of my opponent's development before I determine whether to castle long or short...or even at all. In my opinion, castling early like this only gives your opponent an edge in how to develop his/her forces against your king.  It is also not much of a benefit to castle this early when your rook is still locked in behind its pawns. ~The Doctor