It's okay.  Though you don't have to roll initiative each round; you keep the initial order throughout the encounter.  And unfortunately, a bat bite is (1d3-4) damage, a minimum and maximum of 1 damage, and technically, it would provoke an attack to enter a dog's space to bite, having a reach of 0 feet.<br/><br/>Of course that's just me being petty, and the DM can make familiars more combat capable if he wants.  Usually they just hang out on your shoulder, be cute, scout around, and when you're higher level, maybe deliver a touch spell.  I've just been keeping my fox familiar in my kimono ;)