The spirit of the nation began with the Declaration of Independence, I’ll grant you that. But, the legal entity came into being with ratification of the Articles of Confederation by the States. Citizenship is a legal concept, that was in dispute with the former sovereign to greater or lesser degree over the best part of four decades, and it took two wars to settle once and for all.
Given they won their independence, I retrograde to 1776 since the Congress called it the “United STATES of America” instead of the United Colonies. If they hadn’t won, it’d be moot.
And then you could argue the Articles or perhaps the Treaty of Paris instead, since Britain would have to relinquish its claim.