Hi Nat.
In 1967 I was 20, pregnant and unmarried, no living together then and no legal abortions, we got married knowing little about each other, in them days you had to marry more or less. If we get to Nov 07 we will celebrate our Ruby wedding anniversary, we have 2 children now grown up. OK life hasn't always been easy, we have been short of money, had to go without things but the joy our children have given us made it all worth while.
In my 30's I developed a cancer, the treatment left me unable to have anymore children, whilst in the hospital a young woman came in to have her womb removed due to cancer, she had no children and could never have any in the future.
Don't worry about your parents they will support you whatever your decision,even if your Mum does say she is too young to be a Granny!
Your choice is do you have a life now and children later or children first and a life after, whichever you choose make the decision yourself, don't let anybody force you into a decision you are not happy with, if your boss doesn't like the decision, tough, you have rights.
Make a list of the pros and cons, ignore all other viewpoints, go somewhere quiet, away if necessary, on your own and make your decision and stick to it, no matter what anyone says, it's your life you have to live with your decision and any emotional baggage that decision brings.
You can make the correct decision. Good Luck