She's not autistic or a stalker, if anything she has ADHD and hyperfocuses on battling. In reality though, she's probably just a normal teenage girl who found a new friend she's excited about that she can share her passion with. It seems like she also has some feelings for the player character and at that age it's probably something she's never experienced before and doesn't know how to deal with it. What she needs is for Florian to grab her shoulders, look her in the eyes, and kiss her.