ok ill see into upgrading to the newest version
do you know how do i calculate the number of inputs in my transaction to calculate the size?
Just a remark: my post wasn't urging you to upgrade... It was warning you the account function is depreciated and will be removed in 0.18 (the latest version).
About the fee: if you create and sign a tx in the cli of bitcoind, you can always decode the signed tx before you broadcast. You'll get a json that shows you both size and vsize. If you don't like the fee in sat/vbyte, you can skip the broadcasting and re-create a tx with a better fee in sat/vbyte