Good friends of ours have a DS 5 months younger than our DS1 and we could tell by about 2yrs old that he was on the spectrum - he just did stuff that no other kid ever did and in a way that had all the alarm bells ringing. Our friends just passed this off as him being 'busy' or 'full on' but it was more than that - we could all see it, but they couldn't and until they could, then we had to just wait otherwise they would have completely shut us out and gone into denial about it. Luckily the preschool teachers picked it up within weeks of him starting and they set the ball rolling for a dx and once that happened, his parents were accepting that there was a problem. We did tell them that it wasn't a surprise to us and they both asked why didn't you say anything, but we knew them better than that and said how we knew they wouldn't have listened so we waited. For them, they needed to hear it from someone in authority - not a friend. But this is just a ****ty situation that there is no easy way to do it. I think because you aren't directly friends with her then there isn't a friendship to loose so to speak, but it may also make it hard for her to listen to what you have to say without getting upset or offended.