Bobbi Kristina sparked controversy she and 'her adoptive brother' Nick Gordon are set to wed after stepping out with a diamond ring on her wedding finger.But a spokesperson for the 19-year-old has told MailOnline, yesterday, that Whitney Houston's only daughter is not engaged and the ring is actually her late mother's.The denial comes four days after Bobbi's representatives were first contacted by MailOnline after reports surfaced that she and Nick were planning on getting married - her publicist did not comment on the claims.On Friday, Bobbi Kristina, who is mourning the death of her mother, was spotted leaving an AT&T store with Gordon, who Houston raised as her own for 10 years.The two looked happily in love and held hands as they entered and left the store, in their hometown. MailOnline.