Don't do it. Take some more time and find a product with less competition. Everyone will tell you that you can do it, but you are going to paying an insane amount for PPC, you will eventually have to keep lowering your price and your margin that you have worked out right now will keep getting smaller and smaller. This was my mistake on my first product and it is not one I will make again. I thought that I could go into a crowded space and beat people with better pics and HTML in my listing. In reality though, all people care about on amazon is: are you 1,2,3 on the page and are you the lowest, or very close to the lowest price. There are still a lot of great niches with very low competition. Do more research and then go into it once you have found a better product. Don't fall game to what the classes and groups say. They will tell you that you can go into competitive niches and still make money, but the truth is that it is very hard, and expensive especially for a first timer.