This is probably the programmer in me seeping through, but reading the rules, it doesn't explicitly clarify what to do if you have the same number of shields as fire breaths. It explicitly mentions more fire breaths than shields, and more shields than fire breaths, but not if there's the same number. From what I can tell, having the same number counts as a successful defense; I'm just looking for a clarification.
P.S. I love that the example included has the player named "Hiccup"! Should have had the black dragon called "Night Fury".