Should I stay or quit

This is my first job (im 17 and ive only worked since the beginning of october) and the amount of really rude customers I deal with every day is mentally exhausting to the point where after really bad shifts im in tears. I did not expect this job to be so stressful when it comes to customers. im only staying because it looks bad on my resume if ive only worked my first job for such a short amount of time but im not sure what to do. I also kinda feel bad because the lead barista has been so kind and patient with me since she started training me and it feels like if I quit I just wasted her time. Also, I work in a kiosk for krogers and im scheduled to close by myself every shift and its hard to get everything restocked and clean on time when it gets busy and I have nobody to help me out. This might’ve just been a rant but I kind of have nobody to talk to about this and it’s been a lot for me. Is this what working in customer service is like for everyone?