Hi! Congrats on your pregnancy. I went through the EXACT same thing with my second pregnancy so I know where you are coming from. As far as when to tell the kids that you are expecting, I would say wait until the 2nd trimester, ONLY because I told my son that I was pregnant almost as soon as we found out and then 10 weeks later I had a miscarriage. That was harder to explain why the baby he was so excited for wasn't going to be coming after all. When we got pregnant aain, we waited unti lwe knew all was okay then told him.We made him feel like he was a part of the pregnancy and hyped up the "big brother" thing. I highly recommend that.
As far as your family goes...they'll come around eventually. Most of mine did and those that didn't..they are the ones missing out.Don't let them stress you out and spoil this for you and your boyfriend,ok? Let me know how it goes!Best of Luck