I am trying to find what the legal age to sign a contract in the state of Louisiana was on April 1, 1999.
If a person was under the age of 21 at this time and the legal age to sign a contract (example credit card) in LA was 21 - is the debt owed or voided?
Well, this is where you start when you wish to know more about "Contracts by minors are voidable (CC §1918 et seq.)".
Art. 1918. General statement of capacity
All persons have capacity to contract, except minors, interdicts, and persons deprived of reason at the time of contracting.
Acts 1984, No. 331, §1, eff. Jan. 1, 1985.
That law under your civil code has remained unchanged since its promulgation in 1985.
In 1985, the age of majority in LA was, and remains 18, unless emancipated.
You are trying to argue if one can void a contract entered into as a minor more than 15 years ago.
The court will decide, but I suspect that argument won't fly for the doctrine of "laches" (or your LA equivalent).
You might better argue the SOL on debts, which depends on what type of contract that was entered into.
Here you go:
SOL
State Statute ------------- Written contract Oral contract Injury Property damage
Louisiana La. civil code § 3492 et seq. 10 10 1 1