I agree with RattiesSix.
Weighing her is VERY simple, I do it at home. Get a digital food scale (walmart always has some under $20). Make sure it is able to do grams. If its base is too small for the pigs to sit on, use a bowl. Put the bowl on and zero it out, then place them in it. You should weigh them weekly because their weight is usually the first thing that changes when they get sick. I weigh my 4 boys every weekend. (http://www.guinealynx.info/weigh.html
Pellets, I notice you are in the USA. I loath PetSmart but they do carry Oxbow Pellets. They are pricy but WELL worth it. If you shop online I would HIGHLY recommend KMS Hay loft: http://www.kmshayloft.com/
They sell hay and pellets, both are AMAZING and you will never find anything better than theirs.
Your veggies sound ok but you need to limit the carrots to 1 baby carrot or the side of your pinky. Be careful of the cucumber, it can cause mushy poops.
Do you happen to know what cut your hay is (ask the farmer), if its 1st cut, meaning the first time they harvested it, toss it and get 2nd or 3rd cut. The higher the number the softer and better it is. I personally use a dried grass timothy blend for SUPER softness. (HMS can't ship hay here as far as I know).
Veggies should be 1 cup per pig. (if that helps at all).
Do you know what kind of breed she is? If she is short haired all over, that's called an American short haired, and they tend to look VERY chunky with extra chins (dewlap).