The important event in 1619 was the beginning of self-government in Virginia. Self-government in the colonial era is what set the English colonies apart from the other European colonies and paved the way eventually for the creation of the successful federal system in 1787. The Spanish colonies had a much rockier start after independence because everything had been controlled from Spain and the officials in the colonies were mostly "Peninsulares" born in Spain as opposed to the whites born in the colonies.
Slavery had been going strong in the Americas for more than a century before 1619 on the part of the Spanish, and for a very long time on the part of the native tribes.