In general, I like your thought to take it early and get it out of the way but make sure you prep effectively before you take it. Re: the Science section, it’s more about how to read and analyze graphs/charts than any real knowledge of science. Explore tips on how to excel in test taking strategies.
The only caveat is that next year students will likely be able to take individual sections of the ACT and may impact how you might want to study for these “one-off” tests. For example, you might be better off waiting and studying for and taking one section at a time next year to maximize your scores in each section? My guess is that average scores in each section will go up dramatically and I can envision in a few years a 34 composite might be 85th percentile (vs. 99th percentile currently)?