Well if you are changing your opinions or plans to suit someone else, no, that isn’t right. If you change your mind/plans after careful reflection of all the information and ideas around you, including the ideas presented by your friend, that is a good thing. Perhaps you need to keep a journal and do some real thinking about when and why you change your mind on important topics. I don’t mean superficial ‘stuff’.
If I make a decision that something is right for me, I have usually already gone through a lot of consideration. Even if I made the decision quickly, I will have weighed up the pros and cons and then, if appropriate, done what @Simone_De_Beauvoir suggested, and used my gut feelings. If someone tries to change my mind, part of any reasoning process before I did vary my opinion or plans would be an appraisal of why they want me to do that. What are their motivations.