It's not about "investment".
The opportunity cost of doing things when you're at a low wealth level is enormous.
The obvious example would be to consider the gap between being homeless with $0 and being homeless with $5K.
Your earnings potential just essentially went up by an infinite amount because now you can rent an apartment, get a job, perhaps buy some study equipment like a computer or whatever, and suddenly that $5K can be well north of $50K.
This isn't stock index tracker stuff, this is home economics.
Where exactly are you investing $30,000 that returns more than 100% / year for 8 years?