I believe you're right. I'm quite sure now that he just doesn't want to. I've been struggling together him to write his name for months. Then when his pre-school teacher was here 2 weeks ago, he was supposed to be cutting, and decided to pick up a pencil and write his name on the paper. I could recognise every letter but one, I was amazed. Then he went on to write his younger brothers name! It was spelled write and everything! Not super clear but...just out of no where. Course he wont do it again now. but, lol. He's a stubborn little thing! He also cut out a square an a triangle the other day and did VERY well.
It was nap time and I told him he could either take a nap or stay up if he cut out a square and triangle. Well, he did it, lol. He can also put together 25 piece puzzles by himself no problem, so i don't think there could be a motor skill problem. He just wants to do what he wants to do. (its so frustrating!)
