I have a sophomore now, and we are doing a "soft start" to college planning this year. Asking him to start to think about what he wants in a college-- size, location, specialty.
We are probably on the early side. But my kid is at TJ and will need to choose his junior classes in March or April. After which they are considered locked in and very hard to change. That means he will need to pick his senior lab in a few months, so he can sign up to take the lab pre-recs junior year. So the real question he needs to think about this year is whether he wants to take advanced math and an engineering senior lab and apply to engineering programs, or a more diverse courseload and not go the engineering route. So he needs to be able to choose classes wisely in the spring.
I would like him to have an idea what he wants in a college this summer, so we can do a few campus visits. Especially if he applies west coast or places like Purdue, we are going to need to spread out campus visits-- he's busy even in the summer, we work, and we would like to spread the cost out.
He took the PSAT 8/9 last year, and PSAT practice in a couple weeks. If this year's scores track last year's, he should be in good shape. Various TJ groups partner with Kaplan to offer practice SATs and ACTs a few time a year, so I would like him to take a practice this spring, and see where he needs work, if anywhere. It would be great if he could sit for the SAT once junior year and be done.
So I guess Sophmore year. But if we were not dealing with TJ scheduling issues, probably the summer between sophomore and junior.