When to take SAT/ACT

My school recommends taking the SAT/ACT for the first time no prep in spring of junior year, and then if I want to try to raise my score, study over the summer and retake in fall of senior year. The school says that statistically, people score better when they’re older. A lot of people seem to disagree with this plan, saying it’s crazy to take the test the first time with no prep and it’s crazy to wait to fall of senior year to try to get the score I want since I’ll have so much else to do senior year. But I have a lot to do junior year too. I’m wondering if anyone out there did it the way my school suggests and if you can share your experience.