It is right and truthful to tell every little child that he or she is special. Each is special in relationship to loved ones and based on God making each one-of-a-kind. A child's potential is untested and wide open. Once a foundation of unconditional love is set, growing children and teens benefit from being challenged and supported to learn that being an adult also includes accepting that most of us aren't all that special.
Not being all that special is a relief. There's less pressure and scrutiny when we accept that there is always someone smarter, more athletic, kinder, more popular, cuter, more handsome, funnier, more spiritual, better dressed, more achieving, etc. Not being all that special puts things into perspective. Not everyone can be President of the United States but God has a perfect plan for each one of us. Not being all that special encourages being humble and kind. If we think we're too special, we will look down on others and miss opportunities to improve.
"You are special" rings shallow, naive, and disrespectful if discussion stops there. You want to actually be special because you love God and treat others with respect. You own and handle your short-comings and are striving to fulfill your potential. Then you become special, in a more adult-like way, because you don't need to be all that special.