Are you a member of the Southern Baptist Convention?
Nah, I've heard of the Southern Baptist Convention but I'm not very religious.
Ok
It's pretty interesting though, since it has over 15 million members.
It is a church?
It is more of a Baptist denomination, so yes it is a church for the most part.
Ok. When was the convention founded?
United States who split with northern Baptists over the issue of slavery, specifically whether Southern slave owners could serve as missionaries. After the American Civil War, another split occurred when most freedmen set up independent black congregations, regional associations, and state and national conventions, such as the National Baptist Convention, which became the second-largest Baptist convention by the end of the 19th century. 
Since the 1940s, the Southern Baptist Convention has shifted from some of its regional and historical identification. Especially since the late 20th century,
Church under the Garo Baptist Convention make up perhaps the largest denomination in Meghalaya with 3,00,000 baptised adults concentrated mostly in the Garo Hills. However,it should be understood that the Baptists count only the adult baptised members. The minors and unbaptised members born in a baptist family are not counted as the full-fledged members of the church though such members are very much part of the baptist church and activities. With inclusion of unbaptised Garo baptists, the total Baptist population is about 8,00,000.Baptists do not practce infant baptism but baptises only adults