Yes. In DnD a first level character is generally assumed to already be fully trained in their class at the very least. Achieving a class level is a big deal and the vast majority of people in the world never do it. Even fighters are extraordinary.
"Not every member of the city watch, the village militia, or the queen’s army is a fighter. Most of these troops are relatively untrained soldiers with only the most basic combat knowledge. Veteran soldiers, military officers, trained bodyguards, dedicated knights, and similar figures are fighters."
From DnD Beyond. At level 1 you're already considered to be a professional soldier or the equivalent to a knight who has spent most of their formative years being trained for war.