5'4, 130 lbs, 36b. Would like to know if 400cc to 500cc is going to be to big for me and if I need to reduce the nipple? (photo)

From your photo you are a great candidate for breast augmentation. As for sizes you should seek an in person consultation with a board certified plastic surgeon to try on sizers and take measurements of your chest to determine the right implant for your frame. Best of luck.

Based on the photograph you look like a good candidate for breast augmentation.  If you like the way the 500 sizer looks on you, then it is the right size.  I think reducing the nipple will give you an over operated look.

There are 2 factors to consider when choosing implant sizes.Your breast dimensions/qualities (breast width, tissue quality, skin tone)You goals from the surgery (full upper pole, natural vs. fake look, cleavage)The breast dimensions determine the range of implants which will fit your breast. Your goals from surgery allow for sizing within those dimensions.In your particular case, your breasts may certainly fit a 400cc or 500cc implant, but the result may be an overly "fake" look. Sizing systems can help make a decision, but the most important factor is having a frank discussion with a board certified plastic surgeon on exactly what you are looking for. It's best to meet with at least 2-3 plastic surgeons before committing. 

Thank you for the question and photographs.  Based on your photographs, I think that you are starting at a great place and should have a very nice outcome with breast augmentation surgery.   
Generally speaking, the best online advice I can give to ladies who are considering breast augmentation surgery (regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully.  Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals  with your plastic surgeon. This communication will be critical in determining  breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as  “natural” or "C or D cup”  for example may mean different things to different people and therefore prove unhelpful.
 Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup  size may also be inaccurate. Again, best not to discuss your goals and/or judge the outcome of the procedure performed based on achieving a specific cup size. The use of pre operative computer imaging may be very helpful. 
 3.  Once you feel you have communicated your goals clearly,  allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals.  Again, in my practice, this decision is usually made during surgery. I generally select appropriate breast implant size/profile after the use of temporary intraoperative sizers and viewing the patient's chest in the upright and supine positions.
I hope this ,and the attached link (dedicated to breast augmentation surgery concerns), helps.

Size is very relative to several factors that need to be discussed during in-person consultation with a board certified plastic surgeon.  The size chosen depends on the quality of the skin, postoperative cup size goal, and base width of the breast.  Most likely, if you choose the correct implant and you want to go that large, an implant of that size can be used.  For a larger sized implant on a smaller frame, you may have to go with a higher profile implant with a narrower base width so that the implant doesn't appear wider than your chest.  The nipple very well may stretch when an implant is placed but you may want to wait and do an areola reduction at a later time just in case it doesn't stretch too excessively.  That being said it may be a good idea to correct any nipple asymmetry found during consultation with a small lift at the same time. Good luck!

Very very hard to advise via the internet without IN PERSON examination. I think 400 to 500 cc range would be fine. I prefer moderate profile + implants.  

Choosing the size of your breast implant is an important decision in breast augmentation surgery. It is important that you choose a board certified plastic surgeon who has experience with breast augmentation surgery. The size, style and shape of implant used should be based on several factors, including your cup desire, the width of your breast and the type of fullness you are hoping for. Implants come in a variety of sizes with varying base widths. Areola size can be modified at the time of surgery and you might want to discuss with your surgeon the need for a mini lift, primarily on your left side. 

First of all, I would suggest you visit a board certified plastic surgeon in your area for a consultation. Based on the single frontal photo, a 350-400cc high profile implant should give you breasts in a c-cup range. It appears that a left peri-areolar lift would help with nipple symmetry. I hope you find this helpful.