AIBU to feel offended

My DD had her first baby last summer and I have run off my feet babysitting and generally helping out. She relies heavily on my help but whatever I do she constantly criticises me and tells me I am doing things wrong. I am not the most confident of people and I feel she is constantly undermining me. I know there have been significant changes in the way babies are bought up and I generally check on the internet to check I am doing things the right way but whatever I do never seems good enough for her!