How do I stop being so sarcastic and condescending?

Your young and things maybe are getting on your nerves. With these 2 friends ,try backing of a bit it seems that you are being to much with them. Try doing your homework on your own,that way they don't need to tell you that you've spelt a word wrong. Remember they are just trying to help you .if you keep acting nasty TH them im sure that they wont stay around for long.