Did you hit 13 reps on a 5's week or a 1's week or what? What were the minimum reps for that weight?
Just some anecdotal advice from me:
I'm just now finishing up my 5th month since I started a fresh 5/3/1. In my first 1's week on bench, I got 8 reps. Just yesterday, in the fifth 1's week I've had since I started I hit my top bench set for 7 reps. The weight was 20lbs heavier.
Don't worry about starting too light. If you're still hitting 13 reps on your last set 6 months from now, you got a lot fucking stronger.