Normally, at what age will you start to notice the signs of an ADHD child?

I've read that you can begin to see signs at around 4 years old, however, I think that's far too ripe of an age. Many medical professionals believe that too many kids of that age are already pretty hyper and overactive. You should probably see a medical professional and request a proper diagnosis, but maybe this article will help you to understand the basics: http://www.webmd.com/add-adhd/childhood-adhd/features/adhd-in-preschoolers?page=2

Kids as young as 2 or 3 years old can display symptoms of ADHD. Some of these symptoms include inattention, hyperactivity, and impulsivity are symptoms of the condition at any age. However these behaviours occur in children without ADHD as well. Unless the symptoms continue for over 6 months, then the child will not be diagnosed with adhd. http://www.healthline.com/health/adhd/toddlers#RecognizingADHD1

3 years old. My Son has ADHD and is on medication right now. he is in primary 2 now.

I did asked the professionals. They said earliest would be 3 years old.

1 1/2 years