will weight training and protein shakes effect my boxing performance?

Hi, it really depends what you are trying to achieve – go up a weight category? and also how much boxing do you do? I think your question is a bit too pen to easily answer – can you post more details? Cheers.

I’m 15 too, boxing and using protein and weigh 66Kg. I would not recommend for you to lift weight. just drink the protein after you finish your training. you should do push-ups and stuff. lifting weight affects height and I think you should start lifting weight at least at the age of 16.
protein without lifting weight is good too.