Nope. Good thing, too. Hiding behind NAT is the only level of security a lot of people have.
Now, that doesn't mean that you can't get to that ftp server. I'm not sure which direction you are wanting to go, your description isn't really clear.
If the FTP server is at home, you could simply forward the ftp ports coming into the public IP to the FTP server. Of course, if you have the authority to do so, you could do the same at school (you didn't mention if you were a student, teacher, admin, etc).
Either way, keep in mind that FTP servers in general don't provide much in the way of security, so be careful what you forward where.