Almost. 'Every day' is two words. (an adverb - not to be confused with the one-word adjective) and you need a modal verb of ability after the 'so that'.
"I'm working out hard every day so that I'll be able to show off my body on the beach next summer".
As this is a temporary period, referring to something which you didn't do last year and you may not do next year, the present continuous ( 'I'm working out') is correct.