No, only those who have gone through Believers Baptism are considered members of the church. That is not limited to adults.
So how does it work in a SBC church if non-baptized members want to attend? Are they considered “guests”, including the children of parish members? Can they fully participate in the services? Does the SBC accept baptisms from other Christian denominations are valid? How about other baptists? Do they have to re-baptize someone who’s already been baptized in another denomiantion to make them an SBC member?