We love the instinct. Time is the single biggest advantage you have at 21, and a fourplex that genuinely pencils is a legitimate way to use it. There's no urgency to rush, but if a deal shows real cash flow and you can qualify, nothing says wait. One of us planned to buy multiple fourplexes before a primary residence at that age, then got engaged and bought a condo instead, which made the fourplex plan much harder to run later. Early is easier. On financing, FHA is usually the realistic route at that stage: 3.5 percent down with a credit score of 580 or above, versus 20 to 25 percent down on a conventional investment loan. The catch in higher-cost markets is the FHA self-sufficiency test on 3-4 unit properties: 75 percent of the appraiser's market rent for all the units (the 25 percent haircut covers vacancy and maintenance) has to meet or beat the full monthly payment, including taxes, insurance, and mortgage insurance. That test alone can decide whether a given fourplex is doable. Run the numbers conservatively and have an advisor review the deal. Assume less cash flow than the spreadsheet shows, and budget for the roof, the paint, and the systems instead of pocketing every rent dollar. Done right, a property like this can be in strong shape years down the road, though nobody can promise a specific outcome. To see what you could actually qualify for, the free Roadmap conversation (about 20 minutes) is where we run your real numbers.