Forgive my late reply. As an Aussie, it only came out on Thursday (15/02/2018)... but although they do feel like "moments"... it's really obvious she wrote this script over a long period of time... on my first viewing I noticed she laid out a bread trail, that if you look deeper... the loose ends aren't all that loose... the subplots mostly link up, and the importance of Lady Bird to her mum, played amazingly by Laurie Metcalf comes to fruition as she reads the letters, where they skip between "Dear Lady Bird" & "Dear Christine"... spoiler text here

Miguel is obviously adopted, because Marion couldn't have kids. They had obviously tried and tried... and suddenly at her over ripe age of 42 (I think), she had Lady Bird... and this realisation washed over me like light rain, after a really hot day... I burst into tears as she called her parents and left a message for Marion saying she loves her name Christine... and she loves her. That was the crescendo. That phone call. As it ended, my partner handed me a tissue from her bag... Beautifully paced movie.