Una forma mas correcta de insertar un registro

private void InsertData(string connectionString, string firstName, string lastname, string username, string password
                        int Age, string gender, string contact)
{
    // define INSERT query with parameters
    string query = "INSERT INTO dbo.regist (FirstName, Lastname, Username, Password, Age, Gender,Contact) " + 
                   "VALUES (@FirstName, @Lastname, @Username, @Password, @Age, @Gender, @Contact) ";

    // create connection and command
    using(SqlConnection cn = new SqlConnection(connectionString))
    using(SqlCommand cmd = new SqlCommand(query, cn))
    {
        // define parameters and their values
        cmd.Parameters.Add("@FirstName", SqlDbType.VarChar, 50).Value = firstName;
        cmd.Parameters.Add("@Lastname", SqlDbType.VarChar, 50).Value = lastName;
        cmd.Parameters.Add("@Username", SqlDbType.VarChar, 50).Value = userName;
        cmd.Parameters.Add("@Password", SqlDbType.VarChar, 50).Value = password;
        cmd.Parameters.Add("@Age", SqlDbType.Int).Value = age;
        cmd.Parameters.Add("@Gender", SqlDbType.VarChar, 50).Value = gender;
        cmd.Parameters.Add("@Contact", SqlDbType.VarChar, 50).Value = contact;

        // open connection, execute INSERT, close connection
        cn.Open();
        cmd.ExecuteNonQuery();
        cn.Close();
    }
}