There were actually quite a few Spanish colonists in Texas before 1836. The El Paso area began to grow in the late seventeenth century, particularly after Spaniards and Christian Indians fled New Mexico after the Pueblo Revolt broke out in 1680. Several beautiful old missions and houses of worship can be found along El Paso’s Mission Trail.
San Antonio de Bexar was founded in 1718, and the construction of Mission San Antonio de Valero, aka the Alamo, began six years later. San Antonio also has a Mission Trail featuring several eighteenth-century missions.
Mission San Antonio de Valero was closed in 1794.
Well, it all comes down to what “quite a few” means. In 1835 it is generally thought that the population of Texas was about 35K. That was after relatively large immigration from the US. The total was consideraly less before 1800. While El Paso was settled relatively early, it would be hard to call the population large, unless you were comparing it to other settlements at the time.