A little advice please

A little background first. I work my city library, I've been there about 5 years. I LOVE my job. At the moment I'm hourly. There was an opening for 3 salaried positions (all the same position), so I applied. Tomorrow I have my interview, I'm trying to figure out what to wear.

This was my first idea:

 And then I thought, I wonder what this looks like with dress pants:

I'm leaning toward the dress pants. Most of the time I wear jeans to work. Now that it's getting warm out, I'll be wearing more skirts. I just feel I wear skirts a lot too. I never wear dress pants to work. At least, not this job (the pants are part of my uniform for my other job).

I'd love to know what you all think.