If budgies are given the right circumstances and allowed too, they will breed.
As you have already been told, Midnight's young age not only puts her at risk, but it also puts the chicks at risk.
Has she been mating with Bubbles? The eggs will not be fertile if she hasn't and she is still capable of laying eggs that are not fertile.
Given that she has had two clutches at such a young age, she is at very serious risk of developing issues. It takes a lot out of a bird to lay eggs.
Also that she has laid two clutches means she may be a chronic egg layer.
Providing her with a nest box would be the right thing to do if you are in the right place to help raise a clutch.
You need to do some serious research.
I would start with learning how to candle the eggs to see if they are even fertile.
If they are not, you should dispose of the eggs and remove the nest box and not replace it at all.
The forum is a budgie resource so while you have this issue, you need to start reading up about what's best for budgies.
I will provide you with some links to get you started and you should navigate yourself around the forum, looking for more answers should you need them.
Are You Ready To Breed Your Budgies?
Are Your Eggs Fertile?
A Budgie Breeding Diet
Excessive or Chronic Egg-laying in Birds: Causes, Effects, and Treatment
You should also find your nearest avian vet. I would suspect your Midnight is a chronic layer and you should discuss the matter with a trained professional.