When to tell new job I’m pregnant...

So I was working all day and night trying to find a job to help make some extra money for when the baby comes and I finally found a job working as a assistant teacher at a daycare. (I will be working with infants)

Mind you I knew I was pregnant (14 weeks now) but I haven’t said anything yet because 1. I’m still nervous about miscarriage even though I’m in second trimester and 2. I was also nervous to tell a potential job that I was expecting.

So my question is ...should I tell them the day I start (this Monday) or wait till I am 16 weeks when I’ll feel more confident in the pregnancy.