There are several reasons why you might hesitate to start:
The odds of succeeding are low.
It’s uncomfortable.
People will judge.
There’s one particularly compelling reason why you might hesitate to stop:
Stopping effort means an ending of possibility.
The promise of making an effort is the opportunity to enter a world of non-zero probabilities where you have a chance to change the status quo.
It’s never going low odds or difficulty that truly guarantee failure, it’s the decision to never start — to never give yourself a chance in the first place.