As everyone else says it both is and isn't. But it is worth keeping an eye on and write those comments and any other quirks you notice in her red book if you need to go for an assessment in future you have to do a developmental history from pregnancy to their current age so any notes are helpful.
I got very similar comments at Dd's first parents evening, I remember clearly as my nose was firmly out of joint that the teacher could comment on potential deficiencies (PFB 😆) although autism wasn't directly commented on.
DD thrived at Primary, on the school council, chosen for public speaking activities, Mary in the nativity etc etc academically she flew. No poor behaviour ever (unusual in itself). But she was quirky, not fussed by other children really. A little professor talked to her peers in the same way she talked to adults. Has had one continuous friend all throughout school - really common in autistic girls, her friend tends to venture out and hunter gather other people for their friendship group.
Like many the start of secondary was the turning point, too busy, too loud, others not behaving etc what were quirks as a younger child like not liking hand dryers became intolerable in the teen years, she would physically wince as she went past them. She felt she was losing her mind and really struggled with the school environment, dropped extra curriculars and it was taking longer and longer for her to recharge after school.
She was diagnosed at 13, I knew it might be on the cards so had saved up over 4 years (Help2Save account) and managed to get the diagnosis within 6 weeks of contacting the private clinic opposed to the 4+ yrs on the nHS list in my area.
So my advice is watch and wait, save up, note down any quirks, look into the Autistic Girls Network as well.
Noise cancelling headphones and weighted blankets can be game changer if she really struggles with noise or sleep as she gets older.
It's worth saying though, that if she is autistic it isn't the end of the world. Autism impacts people in a range of ways but many autistic peopl live full and happy lives, a diagnosis gives validation and with the right adjustments put in place at home, school and work (providing there aren't other comorbid conditions at play) there is no reason why she won't succeed. The key seems to be getting a diagnosis and support in place before MH spirals at Secondary, the wrong unsupportive school can have a large impact on GCSEs etc and picking themselves up after that but if you watch and wait now you'll be able to step in before that happens.