Me and my family have a 42 inch TV and I think its to small I think we need a 72 inch TV, what do you think .bigger or smaller

72" won't do much good if you can't sit farther back.
I went from 42 LCD to 55 LED borderless and I love it.
Wait until after the new year when prices drop. Put a picture of it under the tree.

At 14 you always think better is best, it only when you grow up you actually realise that is a complete marketing fallacy.
It QUALITY not QUANTITY.