Puppy agressive towards my niece

Question
My choc lab roscoe (14 weeks) is very aggressive with my 56 year old niece. When he was a puoppy she was playing with him in the kitchen and she leaned on the gate a little to much and the gate fell on him. is it possible that he remembers this and is so aggressive towards her or is he as being equal or lower in the pack

Answer
It is very possible that the pup remembers the accident with the gate, but a 14 week old pup is just full of it at that age.  The dog would more likely be scared of your niece rather than aggressive.  Puppies will bite and chase at that age.  And unfortunately, what we might see as bad behavior is typical puppy play among littermates.    

I know you have asked about your dog and your niece in the past already.  If the puppy can't behave around the child, keep the pup on a leash and by your side or in a crate.  Or limit the interaction between your niece and the dog.  I have seen kids that run and shreek and scream when a puppy runs at them which only feeds the frenzy.  You have to make sure that the environment where the kid and the pup play is 200% calm and supervised.  And if the pup gets overly excited, a time out in the crate with a chew toy is an appropriate consequence.

I would also recommend getting in a obedience class and get a trainer you can work with.  Even see if you can bring the child to class with you.