Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You did not learn this reading, so here's a mnemonic to help you to remember:
What do you use your finger for the most? For pointing, of course! Imagine going up to people and saying, "What will you be (ゆび) when you grow up?" Point your finger at the next person, "What will you be?" Keep going until you're just saying, "You be? You be?" with your finger out.
You have such beautiful fingers.
Wow. It's already been a month since I took the lesson of drawing fingers last time, huh?
I just had a sudden pain in my middle finger.