By Daniel Bates Panthers star running back Christian McCaffrey turns 26 today, and girlfriend Olivia Culpo was there to celebrate his latest lap around the sun on Instagram. The 30-year-old SI Swimsuit model captioned a six-pack of couples photos with a very sweet birthday message. Writing: It’s someone’s birthday!! I love you so much Christian. You are the most dependable, inspiring, thoughtful, + grounding person and I feel so lucky to call you mine. Culpo and McCaffrey have been very public with their relationship over the few years or so. Regularly sharing some PDA with their near-seven mi…