jpbimages: we all start somewhere, and getting out there and shooting is the first step. Here's my critiques on these images, hope they help. they're not meant to offend.
1) This photo I believe was taken way to close to the subject. With the 18-55 lens on the wide end, shooting this close, it will cause this wide angle distortion that you see here. (stretching the face to the corners, etc) of course on wide angle lenses, whatever is closer to the subject (nose) will look bigger than it actually is. Be really careful when using anything wider than 40mm or so when shooting really close like this. It an really stretch those corners!
2) this is your best shot. she's kindof hunched over, but other than that she looks relaxed / like she's having a good time. this shot has great potential. scott kelby's photoshop cs4 for digital photographers is a great book 
check it out if you're a photoshop user.
3) i think eye contact w/ this candid shot would have made this shot, her looking down w/ the expression makes it a not so flattering image to me. It's a bit underexposed. framing/composition are ok.
4) way to close to the model on this one again. notice how her nose has enlarged and is spread out further than normal? that's the wide angle again.
overall, you did well for a first shoot I just think you need to keep shooting, listen to all the great people on here, and reshoot reshoot reshoot! I would recommend really watching your backgrounds. The difference between a snapshot you'd throw on facebook and a 16x24 you'd pay to put on your wall is composition, background, proper exposure, and lighting. master those, and there's nothing you can't shoot
best of luck to you
