I don’t think that a skirt suit or pant suit can define the level of position that you are interviewing for. I think this one really depends on the suit. There are some excellent skirt suits that are professional enough to work really well for an interview. Some skirt suits though are just for fashion and aren’t appropriate for an interview. So I would be more careful picking out the skirt suit than the pant suit. You really can’t go wrong with a pantsuit.
What color suit?
A lighter suit may be viewed as less professional. I am not sure what position you are interviewing for but I would go with light gray. In my office, tan and cream colors are worn on casual Fridays. It could be totally different where you are interviewing but I don’t think there is anything wrong with dressing more professional than whoever is interviewing you. I once went to an interview in a black suit and everyone else was wearing jeans. I felt kind of weird but I immediately felt more respected and older because I was wearing a suit. (This was a good thing because I was interviewing for a manager position to manage people that were basically my same age!)