Expect problems and eat them for breakfast.
Go for it now. The future is promised to no one.
The dog that trots about finds a bone.
Be kind whenever possible. It is always possible.
After a storm comes a calm.
Without hard work, nothing grows but weeds.
Things do not happen. Things are made to happen.
Never complain and never explain.
Be thine own palace, or the world's thy jail.
It's always too early to quit.
There's obviously nothing wrong with selling your art - only an idiot with a trust fund would tell you otherwise. But it's confusing to know how far you should take it.