They won´t feel secure in such a tank and that may retard growht and shedding frequqnecy.
Please let them run on natural substrate. A sand clay mixutere or playsand would be a good choice.
Also they need hide boxex, preferably connected to entrance tunnels for sleeping and feeling secure.
Some rock piles should further help to give shelter and also help with shedding.
Having to live on newspaper and glass imposes significant stress to the lizards.
That may be the reason for their non shedding.

Hope that helps

Ingo

P.S.: Right out of the egg, they have a total length of a bit morethan 4" and yearlings typically reach between 12 and 14"-that may give you an idea about their age.