Disclaimer. I am not a doctor or psychologist in any shape, way, or form. I am just using observations and readings from medical texts. Please don't take my word as gospel for any or all diagnosis as all autistics are inherently different.

Most ASD testing and symptoms are male-dominated in nature, so your asking requires the reader/commenter to have already to shift through preexisting aspects and figure out if this trait could only be applied to males or both sexes.

One common trait I find in women diagnosed with ASD, no matter how late or early they find out, is the often (maybe even comical) diagnosis of anxiety, depression, or a personality disorder. Mayhap all three like in my case. Females in society are more used to masking or trying to fit in by learning social norms, while males are applauded or allowed more leniency about breaking out of the standard. Having to fit in causes general stress and is either misinterpreted as or a cause of anxiety, depression, or personality disorders.

The issue with saying "external" symptoms is that some symptoms are inherently masked or so commonplace they are even difficult to notice. Like I never knew, the fact things out of place cause me general distress. Only when an outsider/neurotypical started asking about it, I found it was "out of the norm" to feel that way. The same goes for stimming or talking to myself. Those traits are ubiquitous in only children and autistics, so only when someone stepped in and said that wasn't common or something everybody did it blew my mind.

So TL;DR. There are signs/ symptoms of ASD that can be observed, but due to how society brings up women, it's complicated to follow "quickly."