Have the fluid changed. Sure, go to the dealership first for peace of mind, but if they insist that it is a lifetime fluid and whatnot, then take it to a trustworthy independent shop and he them do it.
I don't see why it wouldn't be DIY, but since it is something you don't do very often, I figure it is worth just paying to have it done.
, you can change your shifter bushings first. This is easier, probably will cost less, and may even be the culprit. You can get a kit from pelicanparts with all the bushings for your car: