Z scores have by construction 0 mean and unit standard deviation, thus a value of -11,22 indicates your protein is 11 standard deviation apart from the mean of reference population. This implies is an extreme outlier (much lower value than expected). If this is good or bad depends on what you want to know....

I wanna know if this is a good model in a protein structure.

Is the model of Aedes' sodium channel. In the literature the most closer sequence this one is de fruit fly (86 % iden)

then -11.2 implies you protein is very far from the model IF the score measures the adherence to the model (BAD), WHILE if the score measures the 'randomness' of the analysed condition (i.e. what expected by chance), then the result is VERY GOOD because your result is practically impossible to be obtained by chance.