Comma before even though

Solution 1:

In your case, you don't need a comma before even though.
There is never a comma between an independent clause (complete sentence) and a subordinate (or dependent) clause.
However, if the subordinate clause comes before the complete sentence, use a comma after it. (source 1, source 2)

In your example, thou gave me wisdom is a complete sentence, and even though I am a child is a subordinate clause.

You have two options:

Thou gave me wisdom even though I am a child.

or

Even though I am a child, thou gave me wisdom.

Solution 2:

You need a comma before the even though.