You're correct...by 47 years.
"Many accounts treat the arrival of the Canary Islanders in 1731 as the founding date for San Antonio. However, there was a sizeable community in place when the Islenos arrived. The soldiers stationed at the Presidio and the local mestizo population that supported them had been around since 1718 when the first missions were established. The essay focuses on this often overlooked community and its sometimes rocky relationship with the newcomers. In time, the distinctions between soldiers and settlers became less important and the two groups merged through intermarriage."