I would wash the paneling down wtih some good ol soap and water first.
Then just apply the paint color she picked if that's what she want's.
Unless you did something to peal any spots or repair any damaged areas, then you should prime those areas.
Or if the existing color on the paneling is darker than the paint you are going to apply...then use a stain blocker primer, it hides more.
on to the next job..........................