I'm certainly don't know every note on my guitar but I can suggest if you practise scales to sing the name of every note as you play it and thoroughly understand the physical relationship of each note to it's next octave and that should make things easier. As you learn the notes in the lower end of the fretboard you can figure out and become familiar with where they are in the higher frets. Don't feel stupid playing with your friends - use the knowledge your friends have of the guitar to your advantage and learn with them.