I have a gas oven (love it). I don't adjust baking temperature. But all ovens are different, gas or electric, you just need to figure out the best number of minutes in this new oven to get the result you want.
I would have taken the cookies out after the 12 minutes, let them cool and check them out. Maybe 1 extra minute would work, or maybe the consistency was perfect at the 12 minutes. You can't really tell by the colour of them.