What is the difference

Today I have been doing Challenge 11 and near the end there are 2 sentences
Don i ddim isio I didnt want to try…
Dwi ddim isio gofyn…I didnt want to ask ?
Are they interchangeable?

No, these are different tenses, so not interchangeable.
D’on i ddim isio = I didn’t want
Dwi ddim isio = I don’t want

Thank you. I think by the end of the challenge my brain was scrambled!!!