The 30-year-old law graduate further tweeted, "It should be a day of love for everyone. May it be blessed!"
Steenkamp was killed in the early hours of Valentine's Day, as she was accidentally shot dead by boyfriend Pistorius at his home in Pretoria, the Daily Mail reports.
Steenkamp was shot in the head, the chest and the arm, according to the South African police.
Pistorius, who reportedly may have mistaken her for a burglar, has been charged with her murder, the paper said.
Pistorius was first seen with Steenkamp last November at an awards ceremony, but she said they were just friends, the paper reported.
Steenkamp's apparent shyness at that time was perhaps understandable given Pistorius's notoriously complex love life, possibly brought about by his sudden financial and sporting success, the paper said.
Last Sunday, Steenkamp was quoted in a local newspaper as saying that Pistorius was an impeccable man who always has her best interests at heart, and on February 1, she tweeted to Pistorius telling him he was beautiful, the paper added.