Like rainstorm said, this is a decision only you can make. Unfortunately, it's impossible to know exactly how you'll feel about something until you've done it.
It sounds like you can't fathom the idea of aborting or adoption, though. If that is the case, you may have to accept the fact that you'll be a mom. If you can't accept any of the options, you'll have to accept the one that will be easiest for you to live with. Having a baby isn't the end of the world, as nearly all the moms on here can tell you.
On the same note, having a baby also isn't something you should just say "OK, fine" to. You have to think about what is best for you, and what's best for the baby if you choose not to abort, and stop considering what other people "want" or "think". In the end, you're the one who will go through everything physically and emotionally.