I was a teenager once, male not female, but still. And I was the father of a teenage daughter once and now I’m the father of a teenage son. I saw this film with my son.

Maybe how you view this film depends on whether you’re a teenager (and/or a girl) and side with the teenager, or you’re a parent and side with the parent. Maybe interestingly, both my son and I thought the same thing – it’s a pretty good film, not special, not great, certainly not Oscar worthy (but then neither was The Post); it tells its rather slight story reasonably well, but never takes off, doesn’t fly, never soars above the clouds – it’s an Easyjet flight to an obscure French airport, it’s not Concorde to New York.

The story is swiftly told. Set in 2002, for no particularly obvious reason, Lady Bird – real name Christine – heads back to Sacramento where she doesn’t want to be, on account of it being dullsville, with her mother – Laurie Metcalf – with whom she has a spiky relationship. And thus we follow a year or so in Lady Bird’s teenage life before she tries desperately to get into a New York college and thus escape her boring life and annoying mother.

She goes to Catholic school, has a chubby (they’re always chubby) best friend, Julia, with whom she falls in and out of friendship, she auditions for the school musical, has a tentative romance with Danny (Lucas Hedges) which ends badly, unsatisfactorily loses her virginity to bad-boy musician Kyle (Timothee Chalamet), attends the prom, argues and fights with her mother who doesn’t understand or believe in her and has a sweet relationship with her weak, unemployed, good-hearted father (Tracy Letts) who doesn’t wear the trousers in this family. She has two ‘siblings’ (adopted, step, fostered, not sure), Miguel and Shelley, with whom she occasionally spars but the relationship between them is unclear and doesn’t go anywhere interesting. And then she gets in to college in New York (big surprise), goes back to using the name Christine and decides she loves her mother after all (even bigger surprise).

Saoirse Ronan as Lady Bird gives a good performance but not a great one. Laurie Metcalf is fine; where has she been all these years since Roseanne? Lucas Hedges seems to be the go to teenage actor de nos jours and reprises his performances from Manchester by the Sea and Three Billboards outside Ebbing, Missouri (both much better films). The music is good and well-chosen.

If it sounds as if I’m struggling to think of things to say, it’s because I am. If you’re a teenager, you’re already living this story and if you’re the parent of a teenager you’ve either been through it, have it to look forward to, or grateful that it wasn’t you; if you’re neither a teenager nor a parent of one, it’s a decent enough drama but would you really care? We were all teenagers once or will be and teenage angst is teenage angst; Lady Bird’s angst is no more interesting than yours was or will be.

At one point Lady Bird falls out with Julia and tells her,

‘Your Mom’s tits are so totally fake.’

‘She made one mistake when she was 19,’ Julia replies.

‘Two mistakes!’ says Lady Bird.

Now, this is quite a good line, if not particularly original but the trouble is that we have not met Julia’s mother nor seen her tits and nor has there been any previous reference to either of them (mother or tits). Which suggests that the screen-writer Greta Gerwig – who also directs – thought of this line and then had to find a way to shoe-horn it into the film, where it hangs suspended, faintly tittering but a propos of nothing. There are a few other good lines – ‘you’ll have plenty of time to have un-special sex,’ – Kyle tells her after their first fumble, but nothing that brings you up short with the depth of its insight or the power of its poetry.

It’s a not-bad film which bows under the weight of expectation, like a ceiling when a pipe has burst. But at least the ceiling doesn’t collapse; it holds steady until a better film comes along.