Currently Related (Culture)

When it comes to culture or beauty a country has, should we retain the present tense to show that they still have the culture we learned/discovered from the past? For example,

a) At first I thought the Arab people must be very barbaric people from what I learned from their history. But later I found out that they are actually a very harmony race. The reason why their history has so many wars is because they were being pushed to war.

b) There are a lot of differences our life here compare to life of people who live in Islamic country. When I was first sent to work in Islamic country, I didn’t know that it is a custom for Muslims to go to mosque on Friday. At that time I asked myself where all the workers were.

c) I was in US once when I was a child. When I first arrived there, I was amazed that guns are actually legalized there.

Can we keep the tenses unchanged for sentences a, b, c?