Convert Electrum wallet (13 words) into standard 12-word wallet)

I recently uncovered a wallet that was “dormant” for a long time, and I have realized that it is an Electrum wallet with a 13 word pass phrase. This is a problem for me, mainly because there’s no Electrum app for iPhone and my computer is practically obsolete (but still working for the time being), and I don’t want to get a new computer. From what I read, there’s no way to convert my pass phrase into a standard 12-word pass phrase, and I have to move my balance onto a new wallet via a normal bitcoin transaction. My question is: how much is this gonna cost me in fees? Or is there a way to transfer it for free, since both wallets belong to me? Also, is BlueWallet a good wallet app? If not, what would you recommend?