Hi dear!
Oh my goodness, it might be your lucky day.

)
When I was a teenager I used to work at my boyfriend's church for summer camp too! ;o)
I'm a Makeup Artist. Used to work with MAC, but for now I'm an Independent Makeup Artist.
I, too, always wondered about what kind of makeup I should be wearing since there are going to be little kids around and many adults watching!
Okay, let me start off by saying that since you have eyes that transition to browns to greens, dark brown or even a soft black eyeliner and mascara would look great on you. Remember that Greens and Browns compliment each other.
It depends mostly on your skin type as well.
If you have a fair complexion, try not to go for any deep or bold colors when choosing to wear any face makeup. Any light pinks or peaches for blush or bronzers would work well for you.
If you have a tanned complexion, a more golden midtone brown bronzer and anything with a golden undertone to it will look great, this will make your face glowy and radiant, and it won't make you look cakey or too obvious.
For your eyes, I suggest you try out a CoverGirl Quad. This includes 4 different eyeshadows and can be found at drugstores like CVS, Walgreens, Target, etc.
I have the Coffee, Mink, Barely Beige, and Mocha Quad one.
Coffee: a midtone brown eyeshadow
Mink: pearly pinky golden eyeshadow
Barely Beige: light beige with a subtle peach pink undertone
Mocha: a light brown
Take the Mocha and apply this all over your lid. Only your lid and not all the way up to your brows!
Take the Mink and apply this gently in your natural crease, where your eye-socket is found.
Take the Coffee and apply this in the outer corners of your eyes. Make sure to blend blend blend to create a perfect finished look and for a softer gradual transition with the Coffee, Mink, and Mocha.
Take the Barely Beige and apply this under your brows, above where you just applied the Mink(crease). This will complete the look and make your eyes pop!
It's perfect because it's so natural, yet it just gives your eyes that little sparkle. It's natural because the colors are natural: browns, pinky peaches, beige, etc.
As for eyeliner and mascara, you can apply a dark brown or soft black color.
Apply a thin line of eyeliner on your top, and bottom if you'd like.
Apply 2 coats of mascara, but curl your lashes before you apply mascara.
As for bronzer or blush, you can apply this gently on the apples of your cheeks, temples, bridge of nose and chin. Don't over do it with the bronzer or blush as this will take all attention away from your eyes onto your face.

)
As for the lips, you can apply a clear or sheer pink lipgloss or your favorite lip balm!
Hope this helped dear! Good Luck and have fun! xo