This is absolutely NOT an immature request for a first grader. I would request a dysgraphia evaluation immediately. If you wait too long, then the school district argues that "the habits are too ingrained and can't be remedied at this point." However, since dysgraphia is not as well researched as dyslexia and dyscalculia, it is doubtful the school district will first, do a decent evaluation and second, offer the services he really needs for this. So you may be looking at requesting an Independent Educational Evaluation (IEE) from a provider who is more familiar with this area and can make recommendations.