I recently heard someone say, "Everyone that comes with you can't go with you". When it's all said and done, "Life is a personal journey". In order to realize your dream one of the most important things you can do is select "like minded" people to associate with. This does not mean you have to cut out family or friends in your life. It just means you are careful not to discuss your dream/project with them if they lack "the vision".
It's tough enough to realize a dream without having "naysayers" in your own camp. Read books by those who have accomplished similar goals, join organizations that contain members who are on the same path as you, attend workshops/seminars...etc You want to be around people who "feed the fire of your dreams" and not those who "have the best intentions" but throw a wet blanket on your dreams.
In all honesty it's the people who are "close to you" or know you best that have a more difficult time seeing you in (a different light). Someone who knows nothing about your past automatically assumes your goals are realistic or within your reach if you are talking the talk and walking the walk. Best of luck!