The Venezuelan rookie, who missed the cut in her previous three tournaments, produced a bogey free round to lead from Mika Miyazato and Park In-Bee.
“There are feelings that I cannot express right now because it is what I have dreamt all my life for,” Felibert said.
“It’s pretty cool to see my name up there but at the same time I have been trying to not think too much about it and just play one shot at a time and enjoy it.
“I’m having a lot of fun.”
Miyazato carded a round of 65 while Park shot a 68 to sit four shots off the lead and tied for second. Brittany Lang produced the round of the weekend so far with an 8-under-par 63 to join Katie Futcher (67), Ai Miyazato (68), Ryann O'Toole (68) and LPGA Championship winner Shanshan Feng (70) a further shot back.
Local favourite Stacy Lewis, who played her college golf for the University of Arkansas, is another shot off the pace after a second round 69.
Two-times former champion Yani Tseng missed her first cut in more than a year as she followed her opening round 73 with a round of 74 on Saturday.
The round of 74 was the world number one’s sixth straight over par round heading into next weekend’s US Women’s Open.
Michelle Wie also missed the cut after a second round 74 continued her miserable season.