Short Essay - Starting a sentence with 'And' = too informal?

Here’s the excerpt -

While at Model UN Conferences, I was not representing myself: I was representing a political player. And, while I may never know exactly how the delegate from Yemen would have behaved in committee…

(the second sentence is so long that mushing these two together would take some editing)

What do you think- too informal?

I do it all the time to avoid overly long sentences. The objective is to communicate effectively, not to be a grammar nazi.

Even conservative grammar authorities agree that coordinating conjunctions can correctly begin sentences. It’s not about formality. You’re referring to a schoolmarm prohibition designed to keep boneheads from writing sentence fragments – not to a rule that ever had any legitimacy at all.

Thank you @GMTplus7 and @WasatchWriter! That was very helpful, and I guess I have my answer.