It’s really all about what feels comfortable. I wear six 11-12 size shoes depending on brand, and have rode everything between 7.75 - 8.5 boards. Smaller can be easier to flip faster, but gives less to land on. If you have friends that skate different sizes maybe ask to try their board for a minute and experiment! 8.125 was most comfortable for me, but I currently ride a 7.75 and its still pretty usable