Hopefully, your parents will respect your descision and stick by you. I was in a similar situation when I was pregnant with my eldest son... I was 18, and my parents suggested that I terminate... I chose to keep him, and raise him on my own... My parents were happy in the end that I had made a mature choice for my life, and it is something I will never ever regret... he is the most amazing 12yr old now.
There will be alot of people that will need to actually get their heads around the fact that you're gonna be a Mum... but, most will come around and be of some kind of support to you. If you know you can do it, than you can... and thats all that matters in the end... it will be you raising your bubbas... not them.
If you ever need to chat, please feel free to email me... my email addy is in my profile.
All the best
Lisa