I did same at the same border, after 350+days here, I was vientiane for 15minutes. The IO was laughing and telling me I have DTV so i can stay long time :)
I was asked for latest payslips after providing the bank statements... they do it for several reasons i suppose, one being to see if they match whats on the statement (in my case, workcation, maybe to see if i really work for the company)... DTV is destination thailand visa :)
Under 50, you can come with tourist visa and go to language (etc) school to convert for 1year ED. What it comes to bank statements, search the group for the embassy you will be applying from