It's sad that communication and understanding didn't get across among them as kids. It's easy to label her friends as garbage but I don't think they had malicious intent, they were just being very immature. It never crossed their minds that what they said might be a burden to her and that while she may have a different way of dating, it's fine for her to go at her own pace in her own way. From the impressions we have of her friends they strike me as a group who date like a hobby, its something they do for fun with casual importance. For her though, she wanted to take it seriously while at the same time too not losing the sense of self she's developing. They are in different places and sadly her friends are not mature enough yet to just listen and support, they're still caught up in their own world.
The one bit of good advice they gave though was to talk to the bf to try to get things across, but her reaction is realistic for a 15 yr old girl. Even though talking about it may have helped, that takes some skill and maturity and even if they had talked the end result still may have been that she wasn't ready to date. As for him, it also would have been nice if he had been able to encourage her to share her honest feelings rather than just quietly accept the breakup, but when you're scared, hurt and don't know what to do that's easier said than done. Relationships have an inherent messiness to them now and then so I thought this so far was a well handled depiction of how a teenage romance might go. It's not just about feelings or caring for the other person, a lot of other things come into play, especially since they're so young.