Christie Brinkley's youngest daughter recently modeled for Seventeen magazine. 17-year-old Sailor Brinkley Cook will appear in the publication's September issue modeling different looks from recent Parsons School of Design graduates. The teenager signed with IMG Models in November 2013. The 61-year-old Brinkley shared a photo from the spread Tuesday on Instagram, and praised her daughter in the caption. "In Seventeen at 17! You glow girl! @sailorbrinkleycook @seventeen magazine photographer @tomschimacher glam team @kristinhilton @jamesdemolet #zaiyalatt." Cook is Brinkley's only child by fourth husband Peter Cook, and half-sister to Alexa Ray Joel and Jack Brinkley Cook.