I feel too fat for my boyfriend :(?

I am meeting my boyfriend i met online for the first time soon (don't judge about internet dating please) and we have been talking for a year. we're both 17 and he is insanely attractive and has a good body and every other girl hes been with has been skinny and pretty. i'm not overweight, but i don't exactly have a good/fit body and im worried that will make him not like me.. i don't know how to be confident about being with him when i'm so focused on not looking like he expects me too, any advice?