I think she's just really nervous. When she first appeared on Ana Ana Shoukai she was also ultra nervous and polite, but in the end she managed to come out of her shell a bit more. Maybe that was because it was only her and two other girls she knows pretty well. This time, it is the first time she's on one of the regular AKB48 shows, a lot of girls, a lot of hosts... so much pressure.
She seems really smart

As expected from our polite, violin playing, super idol.