Aww, nakakabahala talaga yan, naiintindihan ko! White lines on nails can mean a few things, sometimes it's just minor trauma or bumps (babies that age ay laging gumagalaw and playing), pero kung napapansin mo na parang unstable na yung kuko or may signs ng infection, best to have your pedia check it out para sure. One of my mum friends' toddler had similar lines din and turned out okay lang, but doctor still wanted to see it. In the meantime, keep her nails clean and trimmed short so she doesn't pick at them or get dirt underneath. Fingers crossed it's nothing serious!