[will be expanded into a much longer post]
longevity is unique in attracting a lot of outsiders from many stages of life, even people as old as Vince Giuliano, who absorbed an unusually high amount of biochemistry only after his 70s.
first, you don’t need all the hardest courses, but if you’re smart enough, you should do more theoretical/analytical. Many of the smartest people aren’t in aging right now (eg look at high-throughput ppl at the broad institute, many with mathematical/theoretical backgrounds, or look at walter fontana research). biophysics needs more longevity people, but not everyone can fluidly do biophysics.
Physics/CS are more robust majors than biochemistry/chemistry (which are more easily self-studiable). But like, if there’s bioengineering, DO IT. There’s more potential for anti-aging therapeutics in bioengineering. You want as much protein/genome science as you can get.
There are many ppl who influence the aging dialogue who DON’T directly have biology backgrounds (reason@fightaging, Michael Rae, Laura Deming, etc). It’s possible they would be more effective if they had bio backgrounds
Many people hate on biology/biochemistry/neuroscience majors b/c they tend to attract many premeds who aren’t the most creative or smartest (and tend to force classes into valuing the wrong things). So bioengineering/genome sciences, computational biology (eg 6-7 at MIT) if you can do them.
Stanford bioengineering gives you SO many opportunities, as does MIT, even though they don’t officially lead in aging research (most of the most important methods development research is a potential aging-accelerant and has more long-term potential than most current geroscience research). Comparative biology of aging yields lots of insight (look at Alan A Cohen and Steve Austad and Daniel Promislow who came from more evolutionary biology backgrounds).
Elite private universities tend to be more liberal about letting students skip pre-requisites (this is sadly not possible at University of Washington, where you should just flat out not do bio/neuro and instead do bioengineering/genome sciences or CS)
DEFINITELY get physical chemistry and analytical chemistry if you can. Esp physical organic chemistry (much better than most ochem books which focus on arbitrary non-biological reactions - like srsly WHO CARES ABOUT ALKYENE SYNTHESIS).
For some ppl, the right answer is Chemical Engineering. For some people it’s theoretical CS