What is a better way to say this?

Applying for a degree programme in Norge uni. They thought I was a Norwegian because my credentials.

I prefer an interview in French because I can speak Norwegian a bit. I started speaking it when I was four.

it seems long. lets make it short

maybe: I speak Norwegian late?

or

I speak Norwegian after the critical period.

or

I cant speak Norwegian (simple)

but this prones to additional questions

A: I cant speak Norwegian

B: why cant you speak Norwegian?

A: I started speaking it when I was four.

B: Glè mhath