Congrats! A great plant to be a first. Anywhere near those windows would be great. I think you'll find that soon, you are thinking about what to do with the vines, instead of wondering if it needs fertilizer. LOL! Pothos can live happily for decades without any.
The store soil that is already around the roots could have some time-release fert in it, and any new soil you might use if you change the pot, so consider those things before you start adding more. As you probably already know, too much fert can damage plants.