CAPT OF CARJ EXECUTES INCORRECT MODIFICATION OF FMS RTE PRIOR TO HAVING FO VERIFY ITS ACCURACY. TRACK DEV RESULTS.

Narrative

FMS WAS PROGRAMMED CORRECTLY AND THE FO AND I VERIFIED THE ROUTING AT THE GATE. THE RTE WAS 18C; BLGRS7; BWG; WILDER4; MEM. AFTER TKOF; DEP GAVE US A HDG TO INTERCEPT. I PUT CVG IN THE TOP (BLUE) TO INTERCEPT. I HIT THE EXECUTE BUTTON AS I ASKED FOR VERIFICATION. WE THEN NOTICED I HAD SOMEHOW PUT THE WRONG FIX IN THE WRONG SPOT AND MESSED UP THE FMS ROUTING. JUST AS I FINISHED PUTTING ALL THE FIXES FOR THE BLGRS7 AND THE REST OF THE ROUTING IN; ATC ASKED US WHO GAVE US DIRECT BWG? WE TOLD HIM OUR CLRNC WAS BLGRS7; BWG TRANSITION. HE THEN GAVE US DIRECT IIU TO RESUME THE BLGRS7. I KNOW THE CORRECT ORDER IS TO ENTER CHANGES; VERIFY AND THEN EXECUTE. I WAS TOO QUICK TO HIT THE BUTTON WHILE I WAS ASKING FOR VERIFICATION. THIS CREATED THE MESS THAT I HAD TO GO BACK AND CHANGE INSTEAD OF JUST BEING ABLE TO HIT THE CANCEL MODIFICATION BUTTON. AFTER MESSING UP THE FMS; I SHOULD'VE IMMEDIATELY SWITCHED TO GREEN DATA TO MAKE THE INTERCEPT OR JUST PROGRAMMED THE FIRST 2 FIXES TO GET ESTABLISHED BEFORE TAKING THE TIME TO ENTER ALL THE FIXES; VERIFYING; AND EXECUTING. THIS WOULD HAVE GOTTEN US BACK ON TRACK INSTEAD OF WANDERING OFF COURSE; THUS PROMPTING THE QUERY FROM ATC.