Having a hard time creating a flag based on date variables

[Kaley]

I'm trying to create a flag variable and it isn't working. 

The piece I'm having issues with is the Perf='Y' flag (performance flag)

%let start='01Oct2016'd;
data NewGroups;
set groups;
thrudate=today()-45;
if (thrudate gt beg_dt) and (beg_dt >='01Oct2016'd) then Perf='Y'; else Perf='N';
/*if &today. >=&start. then Perf='Y'; else perf='N';*/
/*format thrudate date9.;*/
startdate=&Start.;
/*format startdate date9.;*/
PerfMonths=intck('month',startdate,thrudate);
beg_dt=input(begin_date,anydtdte19.);
/*format beg_dt date9.;*/
where beg_month >='01Oct2016'd;
run;
proc contents data=newgroups;
run;
proc print data=newgroups(obs=20);
run;

[PGStats]

It looks as if you are using beg_dt before you are giving it a value.