“Pushing” her father over would be tough, though not impossible. But most balconies have a railing too high to allow a man to fall over it too easily. I’m 6’4". My 11 year old son is 5’ 1", and quite strong. But if he shoved me while I was overlooking a normal balcony rail, I’m pretty sure I wouldn’t go over the rail- I’d just bang into it.
On the other hand, little kids (and dogs) can definitely trip a much larger man. My son and my dog have done it to me many times. Even then, if a dog tripped me on a balcony, I probably wouldn’t go over the rail. I’d probably fall down on the balcony floor.