Hi,

My names is Jenn, I am a current owner of a sun conure.  She should be
approximately a year old in may.   I have a few questions regarding her.  
Firstly, her beak has changed from a dark black to a creamy tan near the top
of the beak closest to the face and eyes on the crest.  She also has some
slight peeling on her beak.  Are these normal signs of maturing and beak
growth for her?   Could it be nutritional?   

Yes it sounds nutritional, your bird may be lacking minerals and/or certain supplements. I would strongly suggest a trip to the vet to confirm this and find out exactly what the issues may be physically

As far as nutrition goes, i have her on a seed diet, mixed with a dried fruit
and peppers mix that i pick up in the pet store, mixed with fruit flavored
pellets (the colorful pellets shaped like little fruit pieces)  she also recieves
some fresh fruits and veggies when i can, but i have the problem of them
going bad before i can serve enough to her, and everything is sold is such
huge portions.  would it be detrimental to make a frozen fruit and veggie mix
that i can make and share with her after i defrost some on a daily basis.. or
would freezing the fruit and veggies take away from the nutritional value for
her?

You say that you have her on a seed diet mixed with dried fruit and peppers if you pick up at the pet store. Without knowing the brand is really hard to make a judgment call whether our differences in seed blends. The fruit flavored pallets shaped like fruit pieces may have a lot of corn filler in the blend.

 You may be interested in a product called Goldenfeast Gourmet Bird Food Pellets for Parrots - Golden'Obles It contains NO added vitamins, artificial or otherwise, NO dyes, NO preservatives, NO processed sugars. The #1 ingredients is NOT corn

Also with the fruits and veggies... what exactly is a good mix of them that i
should offer... i dont want to over do it with one type and cause diarrhea or
constipation, or miss out on other nutrients that she should get... so far i try
to give her broccoli which i hate that she loves (it makes the biggest mess)
she also likes tomatoes, with all the leaves and vines gone of course, grapes
are another favorite, she will pick at oranges, other than that she sometimes
picks at things im eating.  one of her favorites to steal is multigrain chips, but
i try to catch her because of the salt content.  other than fruits and
vegetables, what are some other good things to offer her?  are cheese, bread,
rice, meats, etc good for her, or sparingly or not at all

Very simple way to introduce vegetables in your bird is to buy a generic 1 pound package of frozen mixed vegetables in the supermarket. Take a few ounces out of the freezer in the morning and run some cold water over the veggies for just about three or 4 seconds just enough to take the frost off. This will ensure that the vegetables will stay fresh throughout the day. Introduce the other fruits and veggies in small manageable portions of this way you don't have to be concerned with spoilage