I am going to be using the logistic regression in which I will use L2 Regularization. I have these 4 rolling standard deviation variables. Here are the results of the Augmented Dickey-Fuller Test for stationarity. It says they are stationary according to the p-values which are all below 0.05:
(-18.93610985313199, 0.0, 21, 21551, {'1%': -3.430653469865324, '5%': -2.8616741235464906, '10%': -2.5668413902065788})
(-14.904236674495897, 1.491198925557711e-27, 43, 21520, {'1%': -3.4306539070720308, '5%': -2.861674316767364, '10%': -2.5668414930543557})
(-15.369581186780854, 3.5231827878994372e-28, 44, 21459, {'1%': -3.430654771070804, '5%': -2.8616746986063397, '10%': -2.5668416962999574})
(-4.289075846312884, 0.000463964612151969, 15, 21272, {'1%': -3.4306574506058665, '5%': -2.861675882809773, '10%': -2.5668423266289735})
I want to standardize these 4 variables for L2 reg according to this point made here: https://stats.stackexchange.com/a/195391/363734
Here is a before and after standardization, it seems there isn't much of change even though we mean centre around zero. The question I would like to know is, is it better to difference these features before standardizing or should I just keep them as they are and then standardize?:

