Yusra S. answered 10/20/21
Exceptionally Proficient
I would say no.
When writing an essay or paper, it's best to be as concise (clear) as possible and use language that is appropriately formal. If you're writing a paper for academics, you'd want to use short and to-the-point language.
"To start in," is an informal phrase in reference to another, and denotes long-winded, boring and often irritating speech. Additionally, it is most often used not a the beginning of a sentence, but as an action.
e.g. "She started in on all the different ways she could make a casserole."
When beginning a sentence for a list or sequence of events, using "First," or "Firstly," is a better option, but there are other ways of doing so as well. You'll specifically want to look up what are called "transition words."
Good luck!