This is literally 'It is better for me to feed the cat", which is usually transcribed as 'I had better feed the cat' in English.
To make a conditional sentence, ie would, should, we would start with the conditional form of the verb to be eg:-
'Basai hi'n well i fi fwydo'r gath' = (lit) It would be better for me to feed the cat; = I would/should better feed the cat.
If a conditional English translation came up then that was an erroneous one which is no longer in the database.
'fi' is the South Wales for 'me/I' and 'mi' is the North Wales version. They are interchangeable on our course, either is accepted in all sentences.
What's happened here is that since you have a mistake in your original answer "mae'r" should be "mae'n" the system has just offered the next available translation.