I don't think it matters that much, honestly -- my kid did both biology and chemistry his freshman year and physics his sophomore year. They're not that related at this intro level.
Is your kid really interested in science? As the space for electives gets a little less tight, he could always double up one year with two honors level or an honors plus an AP.
I found with my son (now a junior) that we really had to sit down with him freshman year and start mapping out his four-year plan. It seemed crazy based on my HS experience back in the dark ages where it was basically a lockstep progression, but there are so many options and pathways now that you kind of have to look at the big picture to navigate year by year.
We are not at Blair so I don't know anything about it but looking at the website, there's a list of potential pathways for doing the STEM Academy if that's something your kid is interested in. The teachers there might also have some insights that you're not getting from the counselor.
https://www.mbhsacademies.com/uploads/1/1/7/5/117522625/science_technology_engineering___math_pathways_1.pdf