Hedge your bets. Start talking to professors this semester about grad school and getting recommendations. Then tell them later you've decided to do a year of startups\industry. If you are on good terms with them, they will be fine with submitting recommendations 1 year later. You'll just have to let them know what productive things you've been up to in that year. Their only concern is that they aren't damaging their reputation by recommending burnouts.
In the meantime, get involved with other students on building stuff outside of class this year! Once you find a specialty of CS you're passionate about, whether it's statistical machine learning or web development, it'll be obvious which path is the best choice.
In the meantime, get involved with other students on building stuff outside of class this year! Once you find a specialty of CS you're passionate about, whether it's statistical machine learning or web development, it'll be obvious which path is the best choice.