Hatsukoi Harinezumi

Sora Onodera discovers he can use magic one day when he accidentally turns his older brother Riku into a hedgehog. Sora learns that his parents and brother can also use magic, and that he acquired the transformation spell because he’s experiencing his first love. Now the only way to put Riku back to normal is to acquire the magic to undo the transformation, which has the condition that he must first get the girl he likes to tell him she likes him back.

(Source: Hachimitsu Scanlations)