yellowing on bottom leaf but rest are fine?

No, telling yet. Not enough info. what is it growing in, the medium?

Pas grave c est les premieres feuilles voir le 3 étage minimum voir le dessus c est le principal

It's normal for the cotyledons to yellow and falls off. They store food for the roots during the seedling stage so that they can develop enough to start getting nutrients from the soil. Hopefully, I answered your question and remember " Happy Growing and Free your mind one puff at a time ".

Thats normal dont worry. 😋 The plant has more and bigger leaves higher up wich it uses, the lower ones are older and dont get that much sunlight so they are ,,absorbed,, loose colour and fall off eventually. You will see this especially in flower or late flower when even the bigger leaves start yellowing. And personally i would consider repotting your plant into a bigger pot thats not seetrough asap if you can, since that little bottle with that little earth wont give your plants enough rootroom to get some big buds in the end and light isnt very good for roots also😮 have a nice grow cheers

Please cover that see through plastic in something dark. Roots don't like light, and it could be why she'd turning yellow even though you're feeding her.