Hi John, Like most things in life starting early gives you a better chance at success. I started when I was 23 but I would say my start was not traditional. I hope to start writing a blog on bigger pockets about my journey, here is the portion of that journey which applies to your question and my personal experience.
I always liked working on houses growing up, but followed a traditional route after high school. Went to college for 4 years got an engineering degree got a job and started collecting a W-2 check. I quickly realized that working for the "man" was not going to give me an early or comfortable retirement. After working for a year I had gotten to know a couple of other young engineers who shared a similar feeling towards their W-2 jobs. We decided to start an investment club, something very simple, $100/month and we would start investing in stock with the hope of one day having enough money to buy our first house. Jump ahead 5 years and we had saved enough for our first down payment.
So the jump up is I found three like minded people that I spent 5 years getting to know, we had enough cash saved to easily afford our first down payment and feel comfortable that we would have it rented. Many people would argue I took too long and with some respect this is true, the group now looks back and says boy if only we had bought our first house in 2002 instead of 2007. We didn't have the money, we didn't have the relationship, we didn't have the trust at that point. We slow rolled it, but now we have around 4M in property and all the though we are not rich and have not replaced our W-2 job (yet). We all agree its the best decision we ever made.
So find some like minded people, everybody should know which end of a hammer to hold, everybody should probably have good credit scores, and you should be able to trust everybody you are involved with.
Writing that got me more excited for my first blog entry! Anyway good luck