Totally with you on the family and annoying questions thing. My go to line is now "we'll think about it once we have a house" which they know is a few yrs off.
We are planning to tell them about our struggles but only after we announce the pregnancy because we don't want to take away from the surprise. I was reading someone else's post though about their blabber mouth mum - mine is exactly the same. We have discussed keeping the fact it's IVF a secret from everyone except immediate family (hubbys wishes) but I don't think my mum will be able to keep quiet! Will be interesting to see how it plays out.