The recent unveiling of chatbots such as ChatGPT has catalyzed vigorous debates about generative AI's impact on how learners read, write, and communicate. Largely missing from these debates is careful consideration of how young people are experiencing AI in their everyday lives and how they are making sense of the questions that these rapidly evolving cultural tools raise about ethics, power, and social participation. Engaging cultural-historical perspectives on technology, the present study drew on student survey and focus group data from English language arts classes in two culturally and linguistically diverse high schools to answer the following questions: (1) How are young people using AI in their everyday lives, if at all?; (2) What do young people identify as key considerations related to AI-mediated writing?; and (3) What ethical and critical considerations, if any, inform young people's sensemaking of and practices with AI? Young people reported using generative AI for diverse purposes in and out of school, including to accomplish routine organizational and information tasks, to entertain themselves through experimenting with AI technologies, and to catalyze their thinking and writing processes. Survey and focus group participants' responses suggested their regular navigation of ethical and critical dimensions of AI use and their contemplation of what it means to be human through and with advancing technologies. Young people also reported a lack of opportunity to examine AI practices and perspectives in school, suggesting the important role schools can play in supporting youths' development of AI ethics.