If you announce your goals to others, you are less likely to make them happen because you lose motivation, studies confirmed.

Reason
#1: Receiving premature praise for a goal makes follow through less likely.
#2: Receiving “person praise” versus “process praise” could decrease your motivation.
#3: If you’re a beginner, getting negative feedback could stop you.
#4: Accountability doesn’t always work.
#5: Hearing about competition might make you back off.

Source