Tyler, I took a look at your profile and portfolio.
Reviews or critiques should always be based on the intended purpose of the model, and that is what I will do here. On that basis, I'd suggest three things:
1. Get a copy of Men's Health magazine and look at the male models in it. That is what is "swimsuit and underwear models" look like.
2. Notice that none of them are 16. (Trust me on that: I've put 22 models into Men's Health magazine, and I know what they look for).
3. Find something else to specialize in. At your age and body style, "swimsuit and underwear modeling" isn't something you should be doing; I greatly doubt you will find any professional opportunities, and further doubt that at this point in your life you should be trying.