hey rob.. firstly I just want to make sure your using Non-clumping litter ? this is very important especially as she’s eating it. Clumping cat litter can cause intestinal blockage so if it’s not non-clumping throw it out ASAP and get non-clumping litter.
other than that just make sure the litter tray is big enough and that she can get in easily. have you weighed her? sometimes that can help with age of your not sure. it generally goes 100gms per week of age so an 4-6 week old kitten if health generally weighs anywhere from 400grams. to 700grams.. you mention she’s a bit wobbly?
keep an eye on that if it worsens get her to a vet. There is also a condition called Cerebellar Hypoplasia that effects kittens from birth this causes imbalance which can be so mild you don’t notice to sever where a cat can’t walk.. there are also slight signs one of which is called attention tremor which looks like a little bobbing head when they are really concentrating on something or “hen pecking” their food. CH is a non progressive condition and one that cause no pain at all and some CH cats have trouble litter training for the first few months and need easy access litter trays with 3 high sides and one low entrance so if CH is a factor be prepared for a few accidents if you don’t have the appropriate tray..I have a CH kitten and they are amazing cats!
again you may not be dealing with CH but I felt I should mention it as you referred to her as a little wobbly