First of all - welcome! Hope you find the site worthwhile... there are a lot of good folks here but there are also a lot of folks who don't know what the hell they're doing but try to make is sound as if they do - so beware!
Without any information (please DO start a diary - diaries help us help YOU!), all I can tell you is that leaves behave this way for a couple of reasons.... overwatering (which is NOT how much water you give at one time but rather the state of being constantly wet), underwatering or a nitrogen toxicity. My guess, from the photos you've given us, is that you're not giving them enough water.... OR the soil is too "hot" for the little one OR you've given it too many nutes for its young age and it can't cope.
Best thing to do here is to start a diary.... it doesn't have to be from the very first day you germinated the seed but go back as far as you can to reconstruct what you've done, what the conditions are, what nutes (if any) you've given her... and then, when you're done, at the bottom of the page there will be a box where you can ask a question - asking it THERE will link your question to your diary so we will have as much information as possible at our fingertips and can give you better advice...
Good luck - and again, Welcome!