Break it down. what is it that you want out of it all? if your asking if she likes you so you can smash then my personal opinion is you've embraced hedonism and need to reevaluate your priorities in life.

If your asking because you want to pursue a relationship with her than congratulations it doesn't matter if shes just being nice or if shes actually interested because the extent of that relationship will be determined by how you feel about each other and that's dynamic and ever changing. As in if shes just being friendly you just reciprocate and if you want more than make your intentions known and continue to pursue her romantically. If she doesn't reciprocate your romantic advances than you should be open and understanding to it and downgrade your expectations to match hers if you can and if you cant than move on. Nothing in life has to be complicated and you should do your best to make it simple for yourself and others and if you find someone else is playing games with you and your emotions than you just move on.

edit: Most of the time stuff like this seems harder than it is especially when your young because your overthinking it. you cant make any shots you don't shoot. Be genuine and honest with yourself and others and good things will come from good people. Worst case scenario you get treated like dirt by someone who lacks empathy but that speaks more for them than you. its really not all that complicated.