Very good performance! It takes a lot of guts to get out there and do what everybody else can easily critique. Kudos to her for having the C.O. Jones to do it!
Here's my critique. First off, my credentials. I've been a working musician/ singer for 15 years now. The last 10 i've spent in Nashville in and around the country scene.
She's got a lot of power, and the songs did a good job of showing that. Let Her Rip is a deceivingly difficult song. The intro is wide open and bare. She fell into a trap that a lot of people do when they are used to singing with tracks. She's a tad late when she starts to sing. A lot of people do it, they wait for the music to cue instead of feeling it and jumping in on top. It can be annoying as heck though for a band that works behind her. I speak from experience, hehe. Suggest that she work with the tracks and a tape recorder so she can listen back and make sure she's right on target.
There's also several spots in that song where you have to go from a high note down to a lower one. She's consistently a bit sharp on the low notes. She just needs to relax a bit and not push the low note so hard. It'll fall right in tune. She had a couple other pitch problems, but nothing that I wouldn't attribute to being nervous as heck. On another pitch note, if she's going to do Let Her Rip again, have her go over the first "let her rip" over and over until she's comfortable with hitting the note. She was waaaayyyy sharp on it until the track got going and gave her a base to key off of. It's tough to do, but with her talent I'm sure she'll get it just fine.
The only other thing I saw was the way she ended her phrases. She's cutting the last word short and not letting it fall off naturally. Make sure she's singing out the entire word and then decaying the note. That one bit right there will go a long way to making her sound more polished. Cutting the last note of a phrase tends to make it sound very choppy.
Keep in mind I'm not picking on her at all. I'm just pointing out things that I ask people to point out when they listen to one of my performances. It's hard to get better if everyone that knows you just says "great job man!" when they're really thinking "that last song sucked." I wish her the best in the competition!