Change your fluid, its simple. Your trans still shifts good, you have nothing to worry about if you change it. Here's a quick outline..

Get transmission pan gasket and filter (about $20 from dealer)
Get 7qts ATF Mercon/Dextron

Remove 5MM hex drain plug from trans pain, let drain
Remove (6) 13MM bolts from trans pan, drop pan and leave it directly under the tranny.
Remove the 3 screws holding the filter on, and be careful, this little filter holds alot of fluid.
Replace filter
Drain pain contents
Put new gasket on
Reinstall pan

If you feel ambitions, drain the tourqe converter, rotate it until you see the drain plug thru the acess hole and drain

If you dont drain the TQ converter, add about 3.5QTS, if you do, add about 7.

John