Yes, most Armenians are Christians and Armenia was the first Christian nation.
Overwhelming majority of Armenians living in Armenia and other countries in the world are members of Armenian Apostolic Church, which is one of the oldest Christian churches in the world.
In 301 AD Kingdom of Armenia became the first country in the world to adopt Christianity as it’s state religion. Republic of Armenia is a secular nation, but more than 90% of it’s population are Christian.
There is also a smaller number of Armenians who are followers of Armenian Catholic Church.