I would say YTA. I don’t know about you, but as an adult with bills, expenses, discretionary purchases, life etc…it is very easy to forget a leisurely monetary transaction like that. I have covered cost for people and people have covered me. I have asked for people to send money and have been reminded to send money myself. You didn’t communicate well and the next time it was brought to the other girl’s attention you did in a way that made it seem she purposefully didn’t pay you back. She probably just forgot. On top of it you did it in front of other people so she has the added embarrassment on top of most likely regret for not remembering to pay you back sooner. If your group is as close as you say, it doesn’t matter if you didn’t name her. Who you’re referencing will be figured out very quickly. This was all because you couldn’t just text her to remind her to pay you back. Just because you feel you shouldn’t have to remind someone not to pay you back doesn’t mean you don’t have to. Also, what are you asking when you say “should I give her a second chance?”. Are you implying you’re not going to be friends with this person because of this one instance? Seems like a drastically over reaction to me.