pick the one that you are most passionate about. i have never even considered dentistry school because i do not feel any drive towards that profession (not to mention i cannot stand looking in people's mouths all day long, hehe). i love what optometry entails, and so i know i will be a great doctor. all i've ever wanted was to get into optometry school, and now that i have, i am ready to work hard and realize my dreams. i hope you will do the same. best of luck.
A few years back, i was also deciding between dentistry and optometry. i decided on dentistry after shadowing both a few dentist and optometrist. i suggest you shadow a few people to help you make your decision. also, your only a freshmen, you have plenty of time to decide what you want to make of the rest of your life, so don't stress it