before you do anything, I want you to think about something. Right now you have a gut wrenching feeling, that this may or may not be your kid. If you do nothing, then you are going to have that feeling for the rest of your life. I personally do not think I could live with that feeling, and possibly dying never knowing. Money, time, dreams, all the things we cling to right now, will mean nothing once you are older. All that will matter to you is family.
On the flip side, if it is yours, you are going to have good days, and bad days as a parent. I knocked someone up when I was 21 as well. Ok, I am happy I have the kid, I love the kid, but at the same time, nearly every hope and dream I had for myself, I had to throw out the window in order to provide and look after my kid. Your life ends the instant you are a parent and being a parent is a really big ask, but it could be the best thing to ever happen for you as well.
It really is hard when you are still a kid, and are having a kid. But for me, I would have to know if its mine.
I dont know about england, but it is actually "rape" if a partner tells you that they are using contraceptive, and is lying (reference: http://cps.gov.uk/legal/p_to_r/rape_and_sexual_offences/consent section on "conditional consent"), so if it is yours, you should be able to have her locked up for rape -> and even if you did not want to do this, you HAVE to, to help others who are also going to fall victim to this.
It does make life harder if the mum is an unfit parent and a S|ut. I do not know if she will make life miserable for you later on, if she tries to get the kid back. Some moms do fight for custody, etc.
If it is proved not to be your kid, well, I guess it is good. You dodged a bullet, and if the child gets adopted by a loving family, they can all have a great life.
I wish you all the best, regardless of what lies ahead.
