I wouldn't breed. I also don't adhere to 1500 exclusively. I weigh her, and if she's a decent weight and has been eating well I give it a shot. I generally wait for them to get a bit bigger before breeding, if only to get more eggs per clutch.
Also why are you feeding 5 mice a week instead of 1 or 2 rats? Best to get her switched over soon. Rats are more nutritious and will make her grow faster.