Public Safety Employee? Penalty?

I am about to retire from a gov agency after 33 years.  I am with the Aviation Security and Public Safety department,  We fall under SDCERS and have a DROP program.  I will be 57 at the time of retirement. With regard to my DROP program.  Am I considered a Public Safety Employee? Because I will only be 57 and not 59 1/2 years old.  Will I have to pay the 10% tax penalty or as a Public Safety Employee will I be exempt from the 10% penalty if I take the money out of the DROP program?  If I am exempt what do I need to prove it to the IRS and retirement agency.  Thank you