Without people who believe in a set of common ideals, values, and virtues and who are dedicated to defending them, there would be no countries.
There is a significant difference between blind patriotism and true patriotism. Blind patriots shut their eyes to the problems that plague their nation while true patriots recognize those problems and see the potential greatness of their society once those problems have been solved.
Without those kind of people, every society on earth would fail. Consequently, it is logical to be proud of your nation's culture and values.
Nor have you done anything for your country's past achievements, and you cannot be proud of something you did not take part in. You CAN be proud of certain things you have contributed to things that are a part of your country, but that does not mean you can be proud of your country as a whole because then you will also have to feel responsible for your country's failures to which you might have contributed to, be it unconsciously done or not.
None of us have any choice in where we're born. So why be proud of your country? Because of its history? Well, that's something you had nothing to do with. And any country's history is bound to have disgraceful elements to it. People uniting under a flag are among the most brutal people in human history.
If you're proud of America, why not also have pride in France, China, Iran or Nigeria? The thing is, if you were born in these places, you would most likely be a patriot of these nations because of the indoctrination you would receive there. Logic points you far away from Nationalism. So far away.
Countries are a concept cooked up by rich people with power. Being a citizen of Earth I believe that patriotism in general is illogical. America won't last forever (just look at the Roman Empire) and this country has far too many ills for me to hang a flag in my apartment. We killed of Native Americans and enslaved African Americans. Do you want to be proud of that? We couldn't legalize gay marriage for such a long time. We don't have a "mind you're own business" philosophy. Patriotism is illogical.
Pride is meant to be a feeling you get from a skill or an accomplishment. You should be just as proud of your height as you were to your country. By chance you were born into a specific country, just like by chance you were born a specific race, eye color, hair color, height, etc. The only reason you should be proud of your country is if you contributed to it in some form e.I. Politician. Be happy for your country, not proud.