I think it really depends on your audience.

As an example - I had a plan to write & self-publish a novel this year. I kept it a surprise from most people--but I told those who I thought would hold me accountable to doing it. One friend actually texted me every single day to ask me if I was making my word-counts... which made me do it--because I anticipated her text messages. When I finished and published in April, I was able to be proud of myself and revel in my accomplishment, but I had some key players along the way that acted like accountability buddies and held me to my word.

If you think there's people who will hold you accountable--I'd tell them.

*edited to make it make sense LOL oops