Yeah - I know it may sound like we're basically flaming you. Which really isn't the case.
It's just that Nurse Sharks are known to grow very large - at least 8-10' when fully grown. So this really isn't a shark that's suited to the vast majority of private aquarists. And as a private SW aquarist - you should have known this before getting this shark. Ultimately you will need a very large swimming pond size shark lagoon (over 20,000 gallons) just to keep this Nurse pup when it reachs adulthood.
To keep this shark for the next 3 years, I would say you need a minimum size pool/lagoon that's at least 12-15' diameter (at least 2,000-4,000 gallons) at very least- A.S.A.P.