i would say that it is not something to become too alarmed about, as it is natural for a boxer puppy to be filled with exuberance and energy. however, this is something that does need to be addressed and corrected, if you do not want it to get worse as she gets older. it might be a bit irritating now, but when she is 60# and full grown, it will be much more painful, especially for your kids. since she knows the "off" command already, i'd say to start with that. just be consistent with her and consistently tell her "off" each and every time she jumps up or you anticipate her jumping up on someone. you can also try re-directing her energy by commanding her to "sit" when she jumps up on someone. this will teach her that she does not get any attention unless all four paws are on the ground, or in a "sit" position. you can also get her used to sitting before recieving such things as treats, pets, allowed outside, before walking through a door, etc. this type of training is sometimes called the (NILF) Nothing in Life is Free method of training. with the main principle being that they get something when they give something.