Celine Dion’s twin sons looked all grown up next to their mom in a rare photo shared by the singer, RadarOnline.com can reveal. Nelson and Eddy, Dion’s children with late husband René Angélil, turned 13 years old last October. Both seem to have marked the journey into teenage-hood by embracing their newfound ability to grow facial hair. The legendary singer, 56, took the twins and her third son, 23-year-oldRene-Charles, to a Rolling Stones concert in Las Vegas over the weekend where the group took the opportunity to snap a photo with Mick Jagger. “This past Saturday, I got a chance to catch th…