Like the other's have said sound like they might be jelous... does your 48 yr old sister have any kids? and do you really know for sure that your 27 yr old sister hasnt tried to have a baby but cant... sometimes we keep the most importain stuff to ourselves then it comes out as been jelous...

either way they dont have the right to put you down... its your choice to have children now and not later... ( I too am another one who started early ) Maybe you will have to have a big sit down and tell them that if they cant support you in this then you wont be putting up with this type of behaviour anymore as you are going to be a mum if they like it or not...

been so young when I had my winkies I am sure my family had a few words to say about it ( more so when we got married at 18 !!! ) but they were smart enough to keep it to themselves... helped I lived in another state lol...

Give them sometime they just have to get used to the idea... they will just melt when they do get to meet the newest member of the family and will no doult feel bad for what they have said....