Not to be blunt, but Gail Zanchelli hated marijuana as a teen growing up on Long Island. “Tried it, never liked it,” Zanchelli, 64, told The Post. Now it’s part of her nightly routine. The Deer Park resident takes 60 milligrams of gummies infused with THC — the main active ingredient in marijuana — before bed to relieve chronic throbbing in her tailbone. She’s part of a budding group of seniors who use cannabis to relax, ease pain, sleep better or manage their mental health.