Try drinking some soda (Pepsi, mountain Dew, or Coke) with caffeine a few hours before party starts or even chocolate earlier in day. Keeps me awake

I'm throwing a birthday party next week and what I know about when I throw a party is that at some point each time I have a party, I get really tired. I don't want that to happen ever again, but I don't know how to do that! Can anybody offer advice or help because I promised myself to throw a really great birthday party...

Thanks for your answers in advance. (By the way I am not old enough for alcohol).