I'm so sorry for you and your partner - this is a horrible situation to be in. The problem is that none of us can know if you'll love parenthood - some reluctant dads do and some don't.
My own brother has decided he never wants children and despite the fact that I have 7, I can fully see his viewpoint.
Children really do take your life over. Everything you do is dictated by them. What time you get up, what time you sleep, which holidays you take, where you live, the type of car you have, whether you go out alone or not, school pick up and drop off times, getting homework done, after school clubs and activities, weekend birthday parties of classmates, having other peoples children round to play when you may have wanted the house to yourselves, what you spend your money on, where the money goes, what type of TV programme you watch and when you watch it, what you eat, when you eat, where you eat ... I know it's a big list and I'm sure I've missed loads but I'm trying to demonstrate that it really does change absolutely everything about your life.
Nothing will be the same from the life you lead now, except perhaps your job and even then you'll probably be more tired.
I'm not saying at all that it's a bad thing but just that you have to be prepared for a paradigm shift in priorities. Her priorities will change too - don't imagine that you'll be the most important thing any more because no matter how much she loves you, her child will come first - it has to really, if you're to become good parents.
My own opinion is that as you've only been together a year it's best not to take that risk as she won't be the free person she was before and you might not like the change but will be stuck paying for and attending to a child that you didn't want for at least 18 years.
I have a friend who accidentally got pregnant at 40 and is now a really lovely mum, who is paying to put her little boy through private school - she loves him dearly and would move heaven and earth for him. However, she still says even now (the little boy is 9) that she would change things if she could go back in time. She has no alone time with her husband (who also loves him dearly but feels the same way) and they both say that having him at 40 (and 47) means that the carefree middle aged life they'd planned and expected hasn't happened and everything revolves around the boy.
They wish it had never happened but abortion wasn't an option for them. So, it's quite possible that you'll love the child and want the best for him/her but still grieve for the life you lost.
They say that they'll never get these years back. By the time their son leaves home they'll be retiring and feel that the best years will have passed them by.
I don't think it's worth the risk for you and certainly it's not worth preventing her answering the call of her biological clock by stopping her having a baby because she will almost definitely resent you for that in the future.
I feel for you. Good luck in whatever you choose.