About Tax!

So this week, we talked about government and free enterprise system, taxes, and government's budget and spending in the class. First we learned when and how governments involve in a free enterprise system, and public goods. Then we learned about taxes including proportional tax, regressive tax, and progressive tax. Lastly, we learned about a government's budget and spending, which includes social spending and connection between tax and a government.
Today I want to talk about proportional, regressive, and progressive tax. In the class, we demonstrated these three taxes by fake money and us. We know that proportional tax is a system that everyone pays the same percentage of tax, progressive tax is a system that people with more income pay higher percentage of tax, and regressive tax is a system that people with less income pay higher percentage. 
So which tax structures should poor and developing countries have? At first, I think progressive tax is the best tax structure among all three. But I start to think that maybe it only affects in big countries which have range of rich and poor. Therefore, I think that proportional tax is the best tax structure for poor and developing countries. I think that way because in poor countries, most of people are poor and they really don't have rich people. Therefore, most of people have almost the same range of income, which makes me think that progressive tax doesn't fit in those countries. On the other hand, proportional tax which people have to pay the same percentage of tax, may fit more in those countries.

What do you think about my opinion?