I had no idea until my kid was in 4th grade. She was speaking in full sentences before she was 18 months. Before she was five she could completely control money (not taxes) but she had an allowance at four. She knew how much things cost and could go to her money and get out for example $17.52 and knew what to expect in change. She was doing 1000 piece puzzles before she was five. I just never even thought about it. I just went along with it. In first grade she told the teacher that she did not know how to do addition because we had never done "addition". In school she was bored out of her mind. She "failed" the gifted screener, COGAT three times. She was the top in her class doing basically self-taught Algebra in 6th grade. She was top in the English class outdoing the curriculum of her school by the end of fifth grade. I thought gifted meant something else... In fourth grade she became existentially depressed. It was a scary time for us. We switched her to a school that placed her immediately into gifted classes and accelerated her math into 6th grade math and her English into 7th grade. One week later and the depression was gone. She had friends for the first time. It was an amazing transformation. We finally got testing from a private person knowledgeable in giftedness and she has scores just shy of DYS levels. As posted in another post..I thought they were just giving me what I wanted since I paid big bucks for it. They told me to have her take the SAT..Again she just missed DYS levels. She is now in an HG which is really an MG program. Currently in 9th grade doing Pre-Calculus getting A's. I STILL DOUBT IT! and as Michaela noted, I do think I doubt my own intelligence. Not sure where I fall on the scale. Wishing to have my own set of tests or something that I could pin over my doubt.