I'm 27 and have two beautiful girls aged 9 and 6 and I'm expecting my first son in march I was scared at first but if u have heaps of support around you you should be fine my daughters can't wait to meet their new brother and they are gonna be great little helpers =)
You have the right to decide whatever is best for you. Seek some advice from a neutral advocate or counsellor to find out what you really want to do. So many things affect your decision: how present and supportive is the father? Can you afford a baby? If you would seek adoption, can you take care of your family while pregnant? Do you have beliefs or values which lead you down a certain path? Be honest with yourself. Its no one else's business but yours. Good luck deciding.
I also have a 8 and 6 year old (girls) and my partner was very excited for the baby. My girla are also very excited im 7 months now and I have finally come to terms with starting over and having another baby it isnt easy but it ia worth it. This is it for me though. Which almost makes things easier knowing im done childbearing after this. Goodluck
You could think of it as this time you will have 2 helpers! You need to start looking at the better side of this instead of the bad! Your going to have another bundle of joy. You get to watch your older children teach this baby all the things you have been teaching them over the years! Truthfully money is tight for everyone these days you just clip a few coupons and cut back on something's! Good luck and remember your strong and have already done this twice before! :)
All I can tell you is follow your heart. You can have the baby and pick a good family for him or her to go to. There are a lot of people who want babies abd can't have one. Just be 100% about your decision