The world we live in today is full of negativity, you will find people saying no, impossible, can't more often than you will hear them say yes, possible and can. So, what does this tell you? You should not expect more than that from them since is already a known fact. What becomes a problem is when you dwell on what they tell you and believe as reality. Les brown once made a statement; "don't let someone's opinion become your reality". Anything being said to you is a mere opinion and not a fact, someone telling you that is impossible for you to do this, or you can't be able to achieve that merely have an opinion which he or she is expressing. The fact is this, when someone is telling you that something is impossible, they are actually imposing their capacity on you that means is impossible for them so, they believe it should be impossible for you and if you agree with them you have unknowingly given someone the power to determine what you can or can't do. The important thing that matters is what you tell yourself, if you can look into the mirror and tell yourself "I know is hard is not going to be an easy path to take but I can do it and I will do it" believe me when I say that is all the affirmation you need. There is an old African adage that says "if there is no enemy within they enemy outside can do us no harm". If you can win the inner conflict of doubt that goes on in your mind, if you can kill that voice within you that keeps on trying to tell you is impossible and you can't do it, if you are able to say to yourself " yes I can and I will period!" What people outside will say won't be strong enough to deter you from what ever path you have chosen.