If you have the 12 words... You don't have a MultiBit Classic wallet... 12 word recovery phrases were used with MultiBit HD.
To restore your wallet... I'd recommend not using MultiBit... Instead, get Electrum, create a new wallet -> standard -> I already have a seed -> click options, select BIP39, enter you seed -> when prompted for a derivation path select m/0'
Refer here:
https://youtu.be/E-KcY6KUVnY