Liking a boy when having no confident.

I like this guy and we been talking online for about 6months. We talk about everything and I really like him. I know someone who knows him.
For a while we been thinking about meeting in person.
Then I told him about this event on Xmas and he wants to come! He coming and I'm not ready to met him. I'm 5'9 and I weight 250 or more and I hate my body. I don't know what to do.