There are scholarships available for quote-unquote non-traditional students and nontraditional student associations that help navigate the transition. But I would talk to people in your chosen field before making the leap or deciding on a major. Ecology, marine bio, and mycology tend to be popular majors that require graduate degrees for any advancement beyond the level of warm blooded autopipetter and most graduates end up leaving the field for something else. Entry level jobs can be hard to come by (especially since a lot are with the feds), internships and research assistantships can be career-defining, and the top schools tend to hog all the good opportunities. Schools often have programs where you can talk to recent graduates. I’d try to take advantage of them when applying.