First i went to the wrong classroom for math. what purpose does this sentnce serve in this paragraph

We always use "first" or "Firstly" in writings at the beginning of the sentence  to describe the order of the factors or elements we want to create.

"First I went to the wrong... sencond

Explanation:

because of all the immigration, america became one big melting pot. the diversity of cultures from all over the world made america somewhat divided as well. people that immigrated stayed with their kind, and their traditions, while native born americans stayed with their kind and their traditions. normally, people born in american scorned the immigrants as well. the new religions also divided america. in summary, it took away from the american culture and identified america as the "melting pot."

i suggest it is anadiplosis