Don't Give Up on your dreams because someone doesn't believe in it.

Many people didn't also believe in the Wright Brothers when they set out to invent the world's first airplane. The investors they approached laughed at them. But the Wright Brothers refused to give up when everyone else gave up on them

In 30 years time, history will remember those who are pursuing difficult dreams today but their critics will be nameless.
I'll rather be a failed DOER than to be a successful talker/critic.