I need to learn to speak wisely, not to give extra infor, unwanted and unnecessary explanation, ....?

I became 40 last week. I always thought by this age I'll be realy wise and behave maturely, but, now I find myself in embarring situations talking extra, or even too frank, to straight of what I think, I find people startle wondering what just happened? I sometimes hurt people and afterwards I have to go and appologize. In a meeting, or with colleagues, I go great, until out of the blue and from no where a very out of order sentence jumps out, I feel I lose my credibility in this way....can you help? please give me your advices and experience, I am so bothered with this characteristic and would like to cure mysefl.