Please post code in to a code box opened on the forum with the {I}, especially a data step that reads fixed column data. The message windows remove white space and may insert other characters so that the data step as posted will not run.
Create an actual DATE valued variable so that things will sort properly, apply a format you want:
data example;
month='September';
year ='2018';
date = input (catx(' ','1',month,year),anydtdte18.);
format date monyy7.;
run;
If you start using the full month name the width of the text may have issues fitting depending on the actual months involved and how many are involved.