I thought the same way you do, I'm a junior now and I took it this summer, I thought it was alot easier to recall the material, esp o chem than it is to let everything sit for another year without reviewing, the only problem taking it early is bio but I never took ap bio in high school and the classes I took before the dat were two semesters of intro bio and then genetics and mol bio of the cell and i still got a 24. A lot of people say its better to wait and take more bio classes but I thought just reading through cliffs was enough, then again the bio is very random and some luck. Overall I got a 23 TS so i'd say go ahead and take it, also if you dont do well you have all year and next summer and you have more time for research next summer or shadowing, and not to mention it feels AMAZING to be finished😀