This week they are 11. Days old in the pic.
I have not seen a massive growth but have added some empty bottles to fill in as humidity domes and have watered yesterday with half a litre but they are already dry?
And they look small I dunno?
The one on the top left has not grown in length at all. It's still about 1cm high.
I'm also seeing yellow tips on the top right plant.
For 11 days I would agree they do seem small .... And if your seeing yellow tips on one I think your babies are trying to tell you something , may be much too much nutrients for them.