Doubt on behaviour of frequency responce of a system
It appears to have -40 dB/decade roll-off in magnitude starting at 1 rad/sec and transitioning to -120 dB/decade roll-off in magnitude at approximately 300 rad/sec (this suggests you have 2 dominant poles that begin to be dominant when f is at 1 rad/sec and 4 additional poles that begin to contribute at f> 300 rad/sec since each pole would contribute -20 dB/decade to frequency roll-off.

In comparison, red is rolling off at -80 dB/decade consistent with 4 poles.  The poles would actually be complex given the frequency peaking in all cases.