I was close with my boss and I told her when I was around 10 weeks. I was a server which required heavy lifting which I was nervous about. Once I told her, she was extremely understanding and didn't let me lift anything heavy.
I'd gwt it out asap. Youre alowed to have your own lifebso there's nothing they can do if they are happy or not
I'm a care assistant and I'm 28 weeks still working,, I plan on working till I'm 34 weeks :) I wouldn't tell ur boss till u start showing