Newbie; can I do this?

Hello! New to WordPress, my hope it to convert my existing website to WordPress. I, however, am NOT a web developer…I’ve used Dreamweaver a good bit and know some HTML. Am I going to be able to build a theme? I read some of the supporting documentation which seems to require me to know PHP, XHTML, and other scary acronyms. Thanks in advance for any help.

GBee