How to convince parents to let me make a FaceBook account ?

[Sally]

Make a deal with your parents that you will add them as a friend and give them full access to your account. Find out what their biggest concern is and try to work from there--for example, if they are worried about you spending too much time on the site, tell them that you will only spend ten minutes a day on the page (and mean it--stick to it!). If their concern is having you tagged in photos, show them that you can disable those features. If they're worried about bullying, tell them that they can monitor your activities and let them know that you'll ask for help if you need it.

Your best bet is to give them access and prove that you can use the site in a trustworthy manner. Tell them that they can delete your account at any time if they think that you aren't using it appropriately. Facebook can be a good tool for keeping up with your friends, but it has to be used responsibly.