You people don't read closely. It was clear that it didn't occur to Akari to have An ask the forest for help until just before she actually did. This is understandable because she still thinks like a human and isn't going to assume her 2-3 year old daughter is going to control a forest. This also explains her choice to follow the Hero while in the forest. Also, on the bottom left panel of page 31, Akari tries to convince them that An's horns and ears are a costume/dress up. We never get to find out if the rest of the Hero's crew buys it because An takes such umbrage with being thought of as human.
Man...some of the posters are really harsh on her.
She was going for a picnic, why would she feel the need to "disguise" her daughter, in fact, she's already dressed as human. Though she shouldn't have let the hero blindly lead her around.