Go for it now. The future is promised to no one.
By failing to prepare, you are preparing to fail.
Problems are not stop signs, they are guidelines.
I can, therefore I am.
Begin to be now what you will be hereafter.
Never complain and never explain.
What you do today can improve all your tomorrows.
The wise does at once what the fool does at last.
If you can dream it, you can do it.
Know or listen to those who know.
In hard-core science fiction in which characters are responding to a change in environment, caused by nature or the universe or technology, what readers want to see is how people cope, and so the character are present to cope, or fail to cope.