I am English. We would say, 'It is good for me' or 'It is o.k for me'. Never, 'It is good to me' of 'It is o.k. to me'. BUT, we can also say 'It sounds good to me' or 'It sounds o.k to me' or 'It seems o.k to me'. You are right. It is confusing. When we give an opinion, we don't start with 'To me'. We can start with 'For me' but we can also start with 'I think ...', 'I feel', or 'In my opinion ...' (more formal). No, Cintia. You are not crazy. It depends on the rest of the sentence. We say, 'For me', it is o.k or 'For me, it is fine'. But people might say, 'To me, it sounds good', or 'To me, it seems fine'. If you are using a verb like 'sounds', 'feels' or 'seems', use 'to me' at the beginning or the end. If you are using 'is', use 'for me' at the beginning or the end. It's hard for me to explain why, because it is natural for me. But I hope this helps.

A more commonly used expression if you are agreeing with a plan would be, "It/That sounds good to me." You could also say, "It/That is fine with me." A slang version is, "I'm good with that." As for your second question, you might say, "To me, it is fine." In this case, you are really using the same statement as the first one but you are dividing the sentence and changing the order of the words... "It is fine to me." becomes "To me, it is fine." They are the exact same words but in a different order and have the same meaning. However, you might put the "To me" in front if you are trying to emphasize your feelings as being different. For example, your friends all say that hamburgers are great but you disagree. You could say, "Hamburgers are gross to me." However, if you say, "To me, hamburgers are gross!" then the sentence seems to show stronger feeling. Of course this also depends on your tone of voice, etc.

We use "to" when something is being moved from one place to another or expresses direction. We us " for" when something is being done to BENEFIT something of someone or when you are trying to express purpose or reason that something is happening. e.g My boyfriend brought lunch to me. (" to me" here means my boyfriend physically carried the lunch and delivered it to me) My boyfriend brought lunch for me. ( " for me" here means he paid for my lunch out of goodwill.)

To me presents your perspective For me presents your feeling about something "to me, I think she is pretty" from my point of view she isn't pretty (to me) "(As) for me, I think ramen is delicious." While you don't feel ramen is delicious, I do.