Investing in startups and small businesses is inherently risky. Standard considerations, such as execution and strategy risk, are often magnified at the early stages of a company.
If you want to learn more about the company you're investing in and associated risks, you can review their Form C.
Your ownership interest could lose all value if a company goes out of business. Also, private investments in startup companies are illiquid instruments that typically take up to five and seven years (if ever) before an exit—often through acquisition or an IPO.