лиха беда начало {proverb}
likha beda na`chalo
~the first step is the hardest
{literally}
Beginning is a hard evil.
Often said to encourage somebody, when the person is about to do (begin) some nontrivial task, work, etc.
See also:
глаза боятся, а руки делают
a good beginning makes a good ending
all things are difficult before they are easy
a good beginning is half the battle