Should I Be The Bigger Person? Or Just Leave it Be?

My best friend won a contest for a spa day and she can bring 3 other people. She wants to bring me, "Friend A" and "Friend B". Friend A and I used to be very close friends until she stopped talking to me a year ago, during our high school graduation after we had a fight and had been experiencing (what I now see as immature and caddy) problems in our friendship. I don't want to turn down my best friends offer of the spa because shes really excited about it but I don't want to just be sitting there looking like I have a chip on my shoulder because Friend A doesn't like me. I feel like if I were to go and just ignore Friend A's prescence that would be really awkward. I probably sound immature to some people but...sorry I don't know what to tell you. Any advice would be greatly appreciated!