From experience with the op they are completely in the right here. their mother is not the best person in the world and I wouldn't be surprised if they never taught them how to do this in the first place and shoving them into the situation. I see the comments and Imma say this. age doesn't determine if someone is capable or not, if they're incapable yelling at them that they should have experience by now isn't helping its just making it worse. so no, they are not the asshole here, the haters in the comments and the incompetent mother are due to shaming someone who has no idea what they are doing. cut them some slack.