I have done this same thing before and will do again!
the key to this in a self defense case is PROVING you were in fear of your life or someone elses life. your toddler child would not take a lot of abuse to be fatal.
if they were"charging" you and threatening you then you were justified...
yes in NYC you probly would get in trouble...same with California...but your in texas! thank God that all states don't follow the idiot law makers of some other states.
old saying rings true "its better to be judged by 12 than carried by six"
oh by the way if they had a knife...the federal kill zone for self defense is 21 feet. so make sure they are close before pulling the trigger!