How long will the coffee i drank wear off in my situation?!

Today, it was my first time drinking a coffee. I had a packet of white coffee.
I probably drank around 1/2 to 3/4 of the cup.
I had it at 10:30 am and I'm a pretty light sleeper.
How long will it be for me to sleep good again? and what time should i sleep?
How many hours will it take to wear off?
Thanks guys.