@Raphael Karger
Don’t try to do too much too quick. You can make a mistake or two at your age and spend the next ten years digging yourself out of the hole.
Here is what I suggest. Find yourself a good paying job and take up construction as your second job. Spend all your free time learning about investing, and honing your construction skills and knowledge. Take side jobs and put every penny you make off them back into a savings account. Build your credit, build your knowledge and build your savings. Always keep and eye on the new upcoming markets and do the numbers over and over and over again. Be creative, think outside the box, try to find ways a deal could work. Study hacks and tips and tricks for expanding income. Make sure that when you do your first multifamily property it’s not really your first, but the first one you pulled the trigger on. You should have looked at hundreds of properties and ran hundreds of numbers and scenarios before you actually pull the trigger on one.
Once you have enough money saved up for a down payment I suggest you pick either a duplex, tri or quad as a starter. Pick one that needs to be rehabbed a bit (this is where the construction skills come into play). I would usually suggest a full 20% down payment saved for your first project to avoid the PMI because, for your your first project, I suggest you get a fixer upper that you can put sweat equity into it. You won't usually be able to get a FHA loan at 3% on a fixer upper because of the restrictions plus that PMI is just throwing money away. Find something that's undervalued if possible and has an ARV at least 40% more than you paid for it. This will help out with your first HELOC later down the line.
Live in one of the units and rent the other ones out as you rehab them. Do the property managing yourself so you can learn how it works and all that’s involved. It will give you the personal skills and knowledge you’ll need later in life when dealing with outsourced property managers. You’ll be tempted to use credit cards to finance the rehabs on your units. I’m not saying it’s not ok to do in small doses every now and then but don’t do it excessively or for long periods of time. Paying 20% interest on a credit card can eat up a lot of profits of rental income. Stick every single dollar you can afford and what you get from your tenants back into paying down the principal of the loan after the units have been rehabbed.
From here you have a few ways to go, you could get a HELOC on the property, use the funds to get your next and move there and repeat, or you could stay where you are at and try to find a good cash flowing property that works with your down payment from your HELOC. By this point you will have gained a lot of knowledge and know some things that you like and don't like and develop your own strategy accordingly. There is no one right way to do it in this business. It takes guts but don't mistake guts for naivety or ignorance. You can protect yourself and avoid pitfalls if you take your time and educate yourself.
Best of luck to you.