It's true. Family are usually the last to support you. It's not unique to you. I recall reading how great authors such as Lewis and Tokien did not have much support from family. Even Jesus...his own brothers did not understand who he was until after his resurrection. Don't be offended or disappointed...we probably do the same thing. It's true, you see, familiarity does breed contempt - or at least doubt. We can't imagine those we know from such close proximity-their faults and annoyances-as being capable of doing something great. So before getting disappointed or wishing family had an interest in our pursuits, let's make sure sure that we are interested in their pursuits as well.
And if they don't have pursuits to be enthusiastic about, then that reveals the other reason family are slow to support...they don't understand vision. And that opens a whole host of other mindsets which block their ability to be interested in what you are creating.
Either way...carry on, setting your face like flint to press forward to the higher calling of our Lord Jesus Christ.
Blessings.