A fictional character of the animated show Big City Greens, Tilly Green has been debated by fans to have autism. Whether or not this would apply to help can be summed predicated on her actions, personality, history, and behavior as they appear on the screen.
Since Tilly is purely fictional, most discussions on here are for entertainment purposes, still, within the autism community, it's fun to consider her personality traits and apply them to common ASD symptoms.
First, Tilly Green is a 12-year-old girl. Most autism diagnoses, when children are screened, occur when a child is very young. However, it's not uncommon for young preteens to be diagnosed, either. Her temperament is tomboyish and slightly odd.
In some circumstances, such as when she's with Cricket, her personality is more on the gregarious side, though at times quite confused when dealing with situations that one her age wouldn't have an issue understanding.
Still, Tilly's personality shines when it counts, though the series sometimes portrays her as lacking in intelligence over trivial matters.
In comparison to autism, like Tilly, some kids harbor great intellect over matters involving repetition or very specific sets of problems.
But when there are issues revolving around solving problems independently, outside of a group, or through some form of initiative, a lack of fortitude may show. Autistic people have a different perspective than others without the disorder, and, like in Big City Greens, this occurred with Tilly.
Superficially, Tilly's personality seems silly but helpful. Although children with autism are capable of helping others, it may not always seem that way to the recipient.
Tilly is more selfless and friendly, while many with ASD have reserved, quiet personalities. Socializing is often an issue, and in the cartoon, Tilly does manage to talk to others with confidence. From this profile, both an argument for and against her having an autism diagnosis could be made.
For example, many with ASD undergo therapy so that by the time they become preteens, can manage their symptoms to a level that might even be undetected by people unfamiliar with its characteristics.
This could be in line with Tilly, though it's just as common to find children with no diagnosis picking up on social cues at a slower rate than their peers.
In short, although Tilly might have been developed as an autistic child, only the producers of the show can answer this question with absolute certainty.